From 04c1c3c4e62a22b424c07d8b03ca6f6aac2dfa7f Mon Sep 17 00:00:00 2001 From: Sui Jingfeng Date: Wed, 9 Aug 2023 06:34:02 +0800 Subject: PCI/VGA: Correct vga_str_to_iostate() io_state parameter type MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Previously vga_str_to_iostate() took "int *io_state", but vga_arb_write() is the only caller and it passes "unsigned int *". Make the vga_str_to_iostate() parameter type "unsigned int *" to match. [bhelgaas: commit log] Link: https://lore.kernel.org/r/20230808223412.1743176-2-sui.jingfeng@linux.dev Signed-off-by: Sui Jingfeng Signed-off-by: Bjorn Helgaas Reviewed-by: Andi Shyti Reviewed-by: Ilpo Järvinen --- drivers/pci/vgaarb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/pci') diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index 5a696078b382..c1bc6c983932 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -77,7 +77,7 @@ static const char *vga_iostate_to_str(unsigned int iostate) return "none"; } -static int vga_str_to_iostate(char *buf, int str_size, int *io_state) +static int vga_str_to_iostate(char *buf, int str_size, unsigned int *io_state) { /* we could in theory hand out locks on IO and mem * separately to userspace but it can cause deadlocks */ -- cgit v1.2.3 From 60b4925d1aeaf0c46e540949c50818b9be2c896a Mon Sep 17 00:00:00 2001 From: Sui Jingfeng Date: Wed, 9 Aug 2023 06:34:05 +0800 Subject: PCI/VGA: Correct vga_update_device_decodes() parameter type Previously vga_update_device_decodes() took "int new_decodes", but the callers pass "unsigned int new_decodes". Correct the vga_update_device_decodes() parameter type to "unsigned int" to match. In vga_arbiter_notify_clients(), the return from vgadev->set_decode() is "unsigned int" but was stored as "uint32_t new_decodes". Correct the new_decodes type to "unsigned int". [bhelgaas: use correct type for ->set_decode() return, commit log] Link: https://lore.kernel.org/r/20230808223412.1743176-5-sui.jingfeng@linux.dev Signed-off-by: Sui Jingfeng Signed-off-by: Bjorn Helgaas --- drivers/pci/vgaarb.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index c1bc6c983932..443cf1a74c0b 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -864,24 +864,23 @@ bail: return ret; } -/* this is called with the lock */ -static inline void vga_update_device_decodes(struct vga_device *vgadev, - int new_decodes) +/* This is called with the lock */ +static void vga_update_device_decodes(struct vga_device *vgadev, + unsigned int new_decodes) { struct device *dev = &vgadev->pdev->dev; - int old_decodes, decodes_removed, decodes_unlocked; + unsigned int old_decodes = vgadev->decodes; + unsigned int decodes_removed = ~new_decodes & old_decodes; + unsigned int decodes_unlocked = vgadev->locks & decodes_removed; - old_decodes = vgadev->decodes; - decodes_removed = ~new_decodes & old_decodes; - decodes_unlocked = vgadev->locks & decodes_removed; vgadev->decodes = new_decodes; - vgaarb_info(dev, "changed VGA decodes: olddecodes=%s,decodes=%s:owns=%s\n", - vga_iostate_to_str(old_decodes), - vga_iostate_to_str(vgadev->decodes), - vga_iostate_to_str(vgadev->owns)); + vgaarb_info(dev, "VGA decodes changed: olddecodes=%s,decodes=%s:owns=%s\n", + vga_iostate_to_str(old_decodes), + vga_iostate_to_str(vgadev->decodes), + vga_iostate_to_str(vgadev->owns)); - /* if we removed locked decodes, lock count goes to zero, and release */ + /* If we removed locked decodes, lock count goes to zero, and release */ if (decodes_unlocked) { if (decodes_unlocked & VGA_RSRC_LEGACY_IO) vgadev->io_lock_cnt = 0; @@ -1472,7 +1471,7 @@ static void vga_arbiter_notify_clients(void) { struct vga_device *vgadev; unsigned long flags; - uint32_t new_decodes; + unsigned int new_decodes; bool new_state; if (!vga_arbiter_used) -- cgit v1.2.3 From b421364a905e05d62f889786d25954c5a4128c80 Mon Sep 17 00:00:00 2001 From: Sui Jingfeng Date: Wed, 9 Aug 2023 06:34:06 +0800 Subject: PCI/VGA: Simplify vga_arbiter_notify_clients() In vga_arbiter_notify_clients(), "new_state" was computed during every loop iteration even though it doesn't depend on anything that changes during the loop. Move the computation outside the loop. [bhelgaas: drop renames that obscure the purpose, commit log] Link: https://lore.kernel.org/r/20230808223412.1743176-6-sui.jingfeng@linux.dev Signed-off-by: Sui Jingfeng Signed-off-by: Bjorn Helgaas --- drivers/pci/vgaarb.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index 443cf1a74c0b..685681b0e5af 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -1477,12 +1477,10 @@ static void vga_arbiter_notify_clients(void) if (!vga_arbiter_used) return; + new_state = (vga_count > 1) ? false : true; + spin_lock_irqsave(&vga_lock, flags); list_for_each_entry(vgadev, &vga_list, list) { - if (vga_count > 1) - new_state = false; - else - new_state = true; if (vgadev->set_decode) { new_decodes = vgadev->set_decode(vgadev->pdev, new_state); -- cgit v1.2.3 From 4582db1d0a41ed07de140a8bfe8e802749579563 Mon Sep 17 00:00:00 2001 From: Sui Jingfeng Date: Wed, 9 Aug 2023 06:34:08 +0800 Subject: PCI/VGA: Simplify vga_client_register() Reorganize vga_client_register() to avoid the goto and the need to save the return value. Update the kernel-doc to reflect -ENODEV on failure. No functional change intended. [bhelgaas: drop "ret" variable, commit log] Link: https://lore.kernel.org/r/20230808223412.1743176-8-sui.jingfeng@linux.dev Signed-off-by: Sui Jingfeng Signed-off-by: Bjorn Helgaas --- drivers/pci/vgaarb.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index 685681b0e5af..93e15dab5501 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -967,27 +967,22 @@ EXPORT_SYMBOL(vga_set_legacy_decoding); * * To unregister just call vga_client_unregister(). * - * Returns: 0 on success, -1 on failure + * Returns: 0 on success, -ENODEV on failure */ int vga_client_register(struct pci_dev *pdev, unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) { - int ret = -ENODEV; - struct vga_device *vgadev; unsigned long flags; + struct vga_device *vgadev; spin_lock_irqsave(&vga_lock, flags); vgadev = vgadev_find(pdev); - if (!vgadev) - goto bail; - - vgadev->set_decode = set_decode; - ret = 0; - -bail: + if (vgadev) + vgadev->set_decode = set_decode; spin_unlock_irqrestore(&vga_lock, flags); - return ret; - + if (!vgadev) + return -ENODEV; + return 0; } EXPORT_SYMBOL(vga_client_register); -- cgit v1.2.3 From cc64ca4b62f5035c87e955f256b338c32dfdbb19 Mon Sep 17 00:00:00 2001 From: Sui Jingfeng Date: Wed, 9 Aug 2023 06:34:07 +0800 Subject: PCI/VGA: Fix typos Fix typos, rewrap to fill 78 columns, convert to conventional multi-line style. [bhelgaas: squash and add more fixes] Link: https://lore.kernel.org/r/20230808223412.1743176-7-sui.jingfeng@linux.dev Link: https://lore.kernel.org/r/20230808223412.1743176-9-sui.jingfeng@linux.dev Link: https://lore.kernel.org/r/20230808223412.1743176-10-sui.jingfeng@linux.dev Link: https://lore.kernel.org/r/20230808223412.1743176-11-sui.jingfeng@linux.dev Signed-off-by: Sui Jingfeng Signed-off-by: Bjorn Helgaas --- drivers/pci/vgaarb.c | 308 +++++++++++++++++++++++++------------------------ include/linux/vgaarb.h | 4 +- 2 files changed, 161 insertions(+), 151 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index 93e15dab5501..5e6b1eb54c64 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -1,6 +1,6 @@ // SPDX-License-Identifier: MIT /* - * vgaarb.c: Implements the VGA arbitration. For details refer to + * vgaarb.c: Implements VGA arbitration. For details refer to * Documentation/gpu/vgaarbiter.rst * * (C) Copyright 2005 Benjamin Herrenschmidt @@ -30,22 +30,21 @@ #include #include #include - #include - #include static void vga_arbiter_notify_clients(void); + /* - * We keep a list of all vga devices in the system to speed + * We keep a list of all VGA devices in the system to speed * up the various operations of the arbiter */ struct vga_device { struct list_head list; struct pci_dev *pdev; - unsigned int decodes; /* what does it decodes */ - unsigned int owns; /* what does it owns */ - unsigned int locks; /* what does it locks */ + unsigned int decodes; /* what it decodes */ + unsigned int owns; /* what it owns */ + unsigned int locks; /* what it locks */ unsigned int io_lock_cnt; /* legacy IO lock count */ unsigned int mem_lock_cnt; /* legacy MEM lock count */ unsigned int io_norm_cnt; /* normal IO count */ @@ -61,7 +60,6 @@ static bool vga_arbiter_used; static DEFINE_SPINLOCK(vga_lock); static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); - static const char *vga_iostate_to_str(unsigned int iostate) { /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */ @@ -79,14 +77,16 @@ static const char *vga_iostate_to_str(unsigned int iostate) static int vga_str_to_iostate(char *buf, int str_size, unsigned int *io_state) { - /* we could in theory hand out locks on IO and mem - * separately to userspace but it can cause deadlocks */ + /* + * In theory, we could hand out locks on IO and MEM separately to + * userspace, but this can cause deadlocks. + */ if (strncmp(buf, "none", 4) == 0) { *io_state = VGA_RSRC_NONE; return 1; } - /* XXX We're not chekcing the str_size! */ + /* XXX We're not checking the str_size! */ if (strncmp(buf, "io+mem", 6) == 0) goto both; else if (strncmp(buf, "io", 2) == 0) @@ -99,7 +99,7 @@ both: return 1; } -/* this is only used a cookie - it should not be dereferenced */ +/* This is only used as a cookie, it should not be dereferenced */ static struct pci_dev *vga_default; /* Find somebody in our list */ @@ -116,20 +116,18 @@ static struct vga_device *vgadev_find(struct pci_dev *pdev) /** * vga_default_device - return the default VGA device, for vgacon * - * This can be defined by the platform. The default implementation - * is rather dumb and will probably only work properly on single - * vga card setups and/or x86 platforms. + * This can be defined by the platform. The default implementation is + * rather dumb and will probably only work properly on single VGA card + * setups and/or x86 platforms. * - * If your VGA default device is not PCI, you'll have to return - * NULL here. In this case, I assume it will not conflict with - * any PCI card. If this is not true, I'll have to define two archs - * hooks for enabling/disabling the VGA default device if that is - * possible. This may be a problem with real _ISA_ VGA cards, in - * addition to a PCI one. I don't know at this point how to deal - * with that card. Can theirs IOs be disabled at all ? If not, then - * I suppose it's a matter of having the proper arch hook telling - * us about it, so we basically never allow anybody to succeed a - * vga_get()... + * If your VGA default device is not PCI, you'll have to return NULL here. + * In this case, I assume it will not conflict with any PCI card. If this + * is not true, I'll have to define two arch hooks for enabling/disabling + * the VGA default device if that is possible. This may be a problem with + * real _ISA_ VGA cards, in addition to a PCI one. I don't know at this + * point how to deal with that card. Can their IOs be disabled at all? If + * not, then I suppose it's a matter of having the proper arch hook telling + * us about it, so we basically never allow anybody to succeed a vga_get(). */ struct pci_dev *vga_default_device(void) { @@ -147,14 +145,13 @@ void vga_set_default_device(struct pci_dev *pdev) } /** - * vga_remove_vgacon - deactivete vga console + * vga_remove_vgacon - deactivate VGA console * - * Unbind and unregister vgacon in case pdev is the default vga - * device. Can be called by gpu drivers on initialization to make - * sure vga register access done by vgacon will not disturb the - * device. + * Unbind and unregister vgacon in case pdev is the default VGA device. + * Can be called by GPU drivers on initialization to make sure VGA register + * access done by vgacon will not disturb the device. * - * @pdev: pci device. + * @pdev: PCI device. */ #if !defined(CONFIG_VGA_CONSOLE) int vga_remove_vgacon(struct pci_dev *pdev) @@ -193,14 +190,17 @@ int vga_remove_vgacon(struct pci_dev *pdev) #endif EXPORT_SYMBOL(vga_remove_vgacon); -/* If we don't ever use VGA arb we should avoid - turning off anything anywhere due to old X servers getting - confused about the boot device not being VGA */ +/* + * If we don't ever use VGA arbitration, we should avoid turning off + * anything anywhere due to old X servers getting confused about the boot + * device not being VGA. + */ static void vga_check_first_use(void) { - /* we should inform all GPUs in the system that - * VGA arb has occurred and to try and disable resources - * if they can */ + /* + * Inform all GPUs in the system that VGA arbitration has occurred + * so they can disable resources if possible. + */ if (!vga_arbiter_used) { vga_arbiter_used = true; vga_arbiter_notify_clients(); @@ -216,7 +216,8 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev, unsigned int pci_bits; u32 flags = 0; - /* Account for "normal" resources to lock. If we decode the legacy, + /* + * Account for "normal" resources to lock. If we decode the legacy, * counterpart, we need to request it as well */ if ((rsrc & VGA_RSRC_NORMAL_IO) && @@ -236,14 +237,15 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev, if (wants == 0) goto lock_them; - /* We don't need to request a legacy resource, we just enable - * appropriate decoding and go + /* + * We don't need to request a legacy resource, we just enable + * appropriate decoding and go. */ legacy_wants = wants & VGA_RSRC_LEGACY_MASK; if (legacy_wants == 0) goto enable_them; - /* Ok, we don't, let's find out how we need to kick off */ + /* Ok, we don't, let's find out who we need to kick off */ list_for_each_entry(conflict, &vga_list, list) { unsigned int lwants = legacy_wants; unsigned int change_bridge = 0; @@ -252,39 +254,44 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev, if (vgadev == conflict) continue; - /* We have a possible conflict. before we go further, we must + /* + * We have a possible conflict. Before we go further, we must * check if we sit on the same bus as the conflicting device. - * if we don't, then we must tie both IO and MEM resources + * If we don't, then we must tie both IO and MEM resources * together since there is only a single bit controlling - * VGA forwarding on P2P bridges + * VGA forwarding on P2P bridges. */ if (vgadev->pdev->bus != conflict->pdev->bus) { change_bridge = 1; lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; } - /* Check if the guy has a lock on the resource. If he does, - * return the conflicting entry + /* + * Check if the guy has a lock on the resource. If he does, + * return the conflicting entry. */ if (conflict->locks & lwants) return conflict; - /* Ok, now check if it owns the resource we want. We can - * lock resources that are not decoded, therefore a device + /* + * Ok, now check if it owns the resource we want. We can + * lock resources that are not decoded; therefore a device * can own resources it doesn't decode. */ match = lwants & conflict->owns; if (!match) continue; - /* looks like he doesn't have a lock, we can steal - * them from him + /* + * Looks like he doesn't have a lock, we can steal them + * from him. */ flags = 0; pci_bits = 0; - /* If we can't control legacy resources via the bridge, we + /* + * If we can't control legacy resources via the bridge, we * also need to disable normal decoding. */ if (!conflict->bridge_has_one_vga) { @@ -311,7 +318,8 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev, } enable_them: - /* ok dude, we got it, everybody conflicting has been disabled, let's + /* + * Ok, we got it, everybody conflicting has been disabled, let's * enable us. Mark any bits in "owns" regardless of whether we * decoded them. We can lock resources we don't decode, therefore * we must track them via "owns". @@ -353,8 +361,9 @@ static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) vgaarb_dbg(dev, "%s\n", __func__); - /* Update our counters, and account for equivalent legacy resources - * if we decode them + /* + * Update our counters and account for equivalent legacy resources + * if we decode them. */ if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { vgadev->io_norm_cnt--; @@ -371,32 +380,34 @@ static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) vgadev->mem_lock_cnt--; - /* Just clear lock bits, we do lazy operations so we don't really - * have to bother about anything else at this point + /* + * Just clear lock bits, we do lazy operations so we don't really + * have to bother about anything else at this point. */ if (vgadev->io_lock_cnt == 0) vgadev->locks &= ~VGA_RSRC_LEGACY_IO; if (vgadev->mem_lock_cnt == 0) vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; - /* Kick the wait queue in case somebody was waiting if we actually - * released something + /* + * Kick the wait queue in case somebody was waiting if we actually + * released something. */ if (old_locks != vgadev->locks) wake_up_all(&vga_wait_queue); } /** - * vga_get - acquire & locks VGA resources - * @pdev: pci device of the VGA card or NULL for the system default + * vga_get - acquire & lock VGA resources + * @pdev: PCI device of the VGA card or NULL for the system default * @rsrc: bit mask of resources to acquire and lock * @interruptible: blocking should be interruptible by signals ? * - * This function acquires VGA resources for the given card and mark those - * resources locked. If the resource requested are "normal" (and not legacy) + * Acquire VGA resources for the given card and mark those resources + * locked. If the resources requested are "normal" (and not legacy) * resources, the arbiter will first check whether the card is doing legacy - * decoding for that type of resource. If yes, the lock is "converted" into a - * legacy resource lock. + * decoding for that type of resource. If yes, the lock is "converted" into + * a legacy resource lock. * * The arbiter will first look for all VGA cards that might conflict and disable * their IOs and/or Memory access, including VGA forwarding on P2P bridges if @@ -428,7 +439,7 @@ int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) int rc = 0; vga_check_first_use(); - /* The one who calls us should check for this, but lets be sure... */ + /* The caller should check for this, but let's be sure */ if (pdev == NULL) pdev = vga_default_device(); if (pdev == NULL) @@ -447,12 +458,12 @@ int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) if (conflict == NULL) break; - - /* We have a conflict, we wait until somebody kicks the + /* + * We have a conflict; we wait until somebody kicks the * work queue. Currently we have one work queue that we * kick each time some resources are released, but it would - * be fairly easy to have a per device one so that we only - * need to attach to the conflicting device + * be fairly easy to have a per-device one so that we only + * need to attach to the conflicting device. */ init_waitqueue_entry(&wait, current); add_wait_queue(&vga_wait_queue, &wait); @@ -474,12 +485,12 @@ EXPORT_SYMBOL(vga_get); /** * vga_tryget - try to acquire & lock legacy VGA resources - * @pdev: pci devivce of VGA card or NULL for system default + * @pdev: PCI device of VGA card or NULL for system default * @rsrc: bit mask of resources to acquire and lock * - * This function performs the same operation as vga_get(), but will return an - * error (-EBUSY) instead of blocking if the resources are already locked by - * another card. It can be called in any context + * Perform the same operation as vga_get(), but return an error (-EBUSY) + * instead of blocking if the resources are already locked by another card. + * Can be called in any context. * * On success, release the VGA resource again with vga_put(). * @@ -495,7 +506,7 @@ static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) vga_check_first_use(); - /* The one who calls us should check for this, but lets be sure... */ + /* The caller should check for this, but let's be sure */ if (pdev == NULL) pdev = vga_default_device(); if (pdev == NULL) @@ -515,20 +526,20 @@ bail: /** * vga_put - release lock on legacy VGA resources - * @pdev: pci device of VGA card or NULL for system default - * @rsrc: but mask of resource to release + * @pdev: PCI device of VGA card or NULL for system default + * @rsrc: bit mask of resource to release * - * This fuction releases resources previously locked by vga_get() or - * vga_tryget(). The resources aren't disabled right away, so that a subsequence - * vga_get() on the same card will succeed immediately. Resources have a - * counter, so locks are only released if the counter reaches 0. + * Release resources previously locked by vga_get() or vga_tryget(). The + * resources aren't disabled right away, so that a subsequent vga_get() on + * the same card will succeed immediately. Resources have a counter, so + * locks are only released if the counter reaches 0. */ void vga_put(struct pci_dev *pdev, unsigned int rsrc) { struct vga_device *vgadev; unsigned long flags; - /* The one who calls us should check for this, but lets be sure... */ + /* The caller should check for this, but let's be sure */ if (pdev == NULL) pdev = vga_default_device(); if (pdev == NULL) @@ -665,7 +676,7 @@ static bool vga_is_boot_device(struct vga_device *vgadev) } /* - * vgadev has neither IO nor MEM enabled. If we haven't found any + * Vgadev has neither IO nor MEM enabled. If we haven't found any * other VGA devices, it is the best candidate so far. */ if (!boot_vga) @@ -696,20 +707,20 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) return; } - /* okay iterate the new devices bridge hierarachy */ + /* Iterate the new device's bridge hierarchy */ new_bus = vgadev->pdev->bus; while (new_bus) { new_bridge = new_bus->self; - /* go through list of devices already registered */ + /* Go through list of devices already registered */ list_for_each_entry(same_bridge_vgadev, &vga_list, list) { bus = same_bridge_vgadev->pdev->bus; bridge = bus->self; - /* see if the share a bridge with this device */ + /* See if it shares a bridge with this device */ if (new_bridge == bridge) { /* - * If their direct parent bridge is the same + * If its direct parent bridge is the same * as any bridge of this device then it can't * be used for that device. */ @@ -717,10 +728,10 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) } /* - * Now iterate the previous devices bridge hierarchy. - * If the new devices parent bridge is in the other - * devices hierarchy then we can't use it to control - * this device + * Now iterate the previous device's bridge hierarchy. + * If the new device's parent bridge is in the other + * device's hierarchy, we can't use it to control this + * device. */ while (bus) { bridge = bus->self; @@ -741,10 +752,9 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) } /* - * Currently, we assume that the "initial" setup of the system is - * not sane, that is we come up with conflicting devices and let - * the arbiter's client decides if devices decodes or not legacy - * things. + * Currently, we assume that the "initial" setup of the system is not sane, + * that is, we come up with conflicting devices and let the arbiter's + * client decide if devices decodes legacy things or not. */ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) { @@ -763,7 +773,7 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) if (vgadev == NULL) { vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n"); /* - * What to do on allocation failure ? For now, let's just do + * What to do on allocation failure? For now, let's just do * nothing, I'm not sure there is anything saner to be done. */ return false; @@ -781,10 +791,12 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; - /* by default mark it as decoding */ + /* By default, mark it as decoding */ vga_decode_count++; - /* Mark that we "own" resources based on our enables, we will - * clear that below if the bridge isn't forwarding + + /* + * Mark that we "own" resources based on our enables, we will + * clear that below if the bridge isn't forwarding. */ pci_read_config_word(pdev, PCI_COMMAND, &cmd); if (cmd & PCI_COMMAND_IO) @@ -864,7 +876,7 @@ bail: return ret; } -/* This is called with the lock */ +/* Called with the lock */ static void vga_update_device_decodes(struct vga_device *vgadev, unsigned int new_decodes) { @@ -889,7 +901,7 @@ static void vga_update_device_decodes(struct vga_device *vgadev, __vga_put(vgadev, decodes_unlocked); } - /* change decodes counter */ + /* Change decodes counter */ if (old_decodes & VGA_RSRC_LEGACY_MASK && !(new_decodes & VGA_RSRC_LEGACY_MASK)) vga_decode_count--; @@ -913,16 +925,17 @@ static void __vga_set_legacy_decoding(struct pci_dev *pdev, if (vgadev == NULL) goto bail; - /* don't let userspace futz with kernel driver decodes */ + /* Don't let userspace futz with kernel driver decodes */ if (userspace && vgadev->set_decode) goto bail; - /* update the device decodes + counter */ + /* Update the device decodes + counter */ vga_update_device_decodes(vgadev, decodes); - /* XXX if somebody is going from "doesn't decode" to "decodes" state - * here, additional care must be taken as we may have pending owner - * ship of non-legacy region ... + /* + * XXX If somebody is going from "doesn't decode" to "decodes" + * state here, additional care must be taken as we may have pending + * ownership of non-legacy region. */ bail: spin_unlock_irqrestore(&vga_lock, flags); @@ -930,10 +943,10 @@ bail: /** * vga_set_legacy_decoding - * @pdev: pci device of the VGA card + * @pdev: PCI device of the VGA card * @decodes: bit mask of what legacy regions the card decodes * - * Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA + * Indicate to the arbiter if the card decodes legacy VGA IOs, legacy VGA * Memory, both, or none. All cards default to both, the card driver (fbdev for * example) should tell the arbiter if it has disabled legacy decoding, so the * card can be left out of the arbitration process (and can be safe to take @@ -947,25 +960,25 @@ EXPORT_SYMBOL(vga_set_legacy_decoding); /** * vga_client_register - register or unregister a VGA arbitration client - * @pdev: pci device of the VGA client - * @set_decode: vga decode change callback + * @pdev: PCI device of the VGA client + * @set_decode: VGA decode change callback * * Clients have two callback mechanisms they can use. * * @set_decode callback: If a client can disable its GPU VGA resource, it * will get a callback from this to set the encode/decode state. * - * Rationale: we cannot disable VGA decode resources unconditionally some single - * GPU laptops seem to require ACPI or BIOS access to the VGA registers to - * control things like backlights etc. Hopefully newer multi-GPU laptops do - * something saner, and desktops won't have any special ACPI for this. The - * driver will get a callback when VGA arbitration is first used by userspace - * since some older X servers have issues. + * Rationale: we cannot disable VGA decode resources unconditionally + * because some single GPU laptops seem to require ACPI or BIOS access to + * the VGA registers to control things like backlights etc. Hopefully newer + * multi-GPU laptops do something saner, and desktops won't have any + * special ACPI for this. The driver will get a callback when VGA + * arbitration is first used by userspace since some older X servers have + * issues. * - * This function does not check whether a client for @pdev has been registered - * already. + * Does not check whether a client for @pdev has been registered already. * - * To unregister just call vga_client_unregister(). + * To unregister, call vga_client_unregister(). * * Returns: 0 on success, -ENODEV on failure */ @@ -991,13 +1004,13 @@ EXPORT_SYMBOL(vga_client_register); * * Semantics is: * - * open : open user instance of the arbitrer. by default, it's + * open : Open user instance of the arbiter. By default, it's * attached to the default VGA device of the system. * - * close : close user instance, release locks + * close : Close user instance, release locks * - * read : return a string indicating the status of the target. - * an IO state string is of the form {io,mem,io+mem,none}, + * read : Return a string indicating the status of the target. + * An IO state string is of the form {io,mem,io+mem,none}, * mc and ic are respectively mem and io lock counts (for * debugging/diagnostic only). "decodes" indicate what the * card currently decodes, "owns" indicates what is currently @@ -1011,7 +1024,7 @@ EXPORT_SYMBOL(vga_client_register); * write : write a command to the arbiter. List of commands is: * * target : switch target to card (see below) - * lock : acquires locks on target ("none" is invalid io_state) + * lock : acquire locks on target ("none" is invalid io_state) * trylock : non-blocking acquire locks on target * unlock : release locks on target * unlock all : release all locks on target held by this user @@ -1028,23 +1041,21 @@ EXPORT_SYMBOL(vga_client_register); * Note about locks: * * The driver keeps track of which user has what locks on which card. It - * supports stacking, like the kernel one. This complexifies the implementation + * supports stacking, like the kernel one. This complicates the implementation * a bit, but makes the arbiter more tolerant to userspace problems and able * to properly cleanup in all cases when a process dies. * Currently, a max of 16 cards simultaneously can have locks issued from * userspace for a given user (file descriptor instance) of the arbiter. * * If the device is hot-unplugged, there is a hook inside the module to notify - * they being added/removed in the system and automatically added/removed in + * it being added/removed in the system and automatically added/removed in * the arbiter. */ #define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS #define PCI_INVALID_CARD ((struct pci_dev *)-1UL) -/* - * Each user has an array of these, tracking which cards have locks - */ +/* Each user has an array of these, tracking which cards have locks */ struct vga_arb_user_card { struct pci_dev *pdev; unsigned int mem_cnt; @@ -1063,9 +1074,8 @@ static DEFINE_SPINLOCK(vga_user_lock); /* - * This function gets a string in the format: "PCI:domain:bus:dev.fn" and - * returns the respective values. If the string is not in this format, - * it returns 0. + * Take a string in the format: "PCI:domain:bus:dev.fn" and return the + * respective values. If the string is not in this format, return 0. */ static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, unsigned int *bus, unsigned int *devfn) @@ -1073,7 +1083,6 @@ static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, int n; unsigned int slot, func; - n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); if (n != 4) return 0; @@ -1098,7 +1107,7 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf, if (lbuf == NULL) return -ENOMEM; - /* Protects vga_list */ + /* Protect vga_list */ spin_lock_irqsave(&vga_lock, flags); /* If we are targeting the default, use it */ @@ -1112,15 +1121,16 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf, /* Find card vgadev structure */ vgadev = vgadev_find(pdev); if (vgadev == NULL) { - /* Wow, it's not in the list, that shouldn't happen, - * let's fix us up and return invalid card + /* + * Wow, it's not in the list, that shouldn't happen, let's + * fix us up and return invalid card. */ spin_unlock_irqrestore(&vga_lock, flags); len = sprintf(lbuf, "invalid"); goto done; } - /* Fill the buffer with infos */ + /* Fill the buffer with info */ len = snprintf(lbuf, 1024, "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n", vga_decode_count, pci_name(pdev), @@ -1166,7 +1176,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user *buf, if (copy_from_user(kbuf, buf, count)) return -EFAULT; curr_pos = kbuf; - kbuf[count] = '\0'; /* Just to make sure... */ + kbuf[count] = '\0'; if (strncmp(curr_pos, "lock ", 5) == 0) { curr_pos += 5; @@ -1191,7 +1201,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user *buf, vga_get_uninterruptible(pdev, io_state); - /* Update the client's locks lists... */ + /* Update the client's locks lists */ for (i = 0; i < MAX_USER_CARDS; i++) { if (priv->cards[i].pdev == pdev) { if (io_state & VGA_RSRC_LEGACY_IO) @@ -1308,7 +1318,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user *buf, curr_pos += 7; remaining -= 7; pr_debug("client 0x%p called 'target'\n", priv); - /* if target is default */ + /* If target is default */ if (!strncmp(curr_pos, "default", 7)) pdev = pci_dev_get(vga_default_device()); else { @@ -1358,7 +1368,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user *buf, vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n", MAX_USER_CARDS); pci_dev_put(pdev); - /* XXX: which value to return? */ + /* XXX: Which value to return? */ ret_val = -ENOMEM; goto done; } @@ -1419,13 +1429,12 @@ static int vga_arb_open(struct inode *inode, struct file *file) list_add(&priv->list, &vga_user_list); spin_unlock_irqrestore(&vga_user_lock, flags); - /* Set the client' lists of locks */ + /* Set the client's lists of locks */ priv->target = vga_default_device(); /* Maybe this is still null! */ priv->cards[0].pdev = priv->target; priv->cards[0].io_cnt = 0; priv->cards[0].mem_cnt = 0; - return 0; } @@ -1459,8 +1468,8 @@ static int vga_arb_release(struct inode *inode, struct file *file) } /* - * callback any registered clients to let them know we have a - * change in VGA cards + * Callback any registered clients to let them know we have a change in VGA + * cards. */ static void vga_arbiter_notify_clients(void) { @@ -1494,9 +1503,11 @@ static int pci_notify(struct notifier_block *nb, unsigned long action, vgaarb_dbg(dev, "%s\n", __func__); - /* For now we're only intereted in devices added and removed. I didn't - * test this thing here, so someone needs to double check for the - * cases of hotplugable vga cards. */ + /* + * For now, we're only interested in devices added and removed. + * I didn't test this thing here, so someone needs to double check + * for the cases of hot-pluggable VGA cards. + */ if (action == BUS_NOTIFY_ADD_DEVICE) notify = vga_arbiter_add_pci_device(pdev); else if (action == BUS_NOTIFY_DEL_DEVICE) @@ -1535,8 +1546,7 @@ static int __init vga_arb_device_init(void) bus_register_notifier(&pci_bus_type, &pci_notifier); - /* We add all PCI devices satisfying VGA class in the arbiter by - * default */ + /* Add all VGA class PCI devices by default */ pdev = NULL; while ((pdev = pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h index ed5e5462f1d2..97129a1bbb7d 100644 --- a/include/linux/vgaarb.h +++ b/include/linux/vgaarb.h @@ -77,7 +77,7 @@ static inline int vga_client_register(struct pci_dev *pdev, static inline int vga_get_interruptible(struct pci_dev *pdev, unsigned int rsrc) { - return vga_get(pdev, rsrc, 1); + return vga_get(pdev, rsrc, 1); } /** @@ -92,7 +92,7 @@ static inline int vga_get_interruptible(struct pci_dev *pdev, static inline int vga_get_uninterruptible(struct pci_dev *pdev, unsigned int rsrc) { - return vga_get(pdev, rsrc, 0); + return vga_get(pdev, rsrc, 0); } static inline void vga_client_unregister(struct pci_dev *pdev) -- cgit v1.2.3