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authorSui Jingfeng <suijingfeng@loongson.cn>2023-08-09 01:34:07 +0300
committerBjorn Helgaas <bhelgaas@google.com>2023-08-24 21:27:47 +0300
commitcc64ca4b62f5035c87e955f256b338c32dfdbb19 (patch)
tree380899539680a6765f4af5475f46c6f943a68fef /drivers/pci/vgaarb.c
parent0215845348fd09a0125da3d9d1a1e2476b49cd70 (diff)
downloadlinux-cc64ca4b62f5035c87e955f256b338c32dfdbb19.tar.xz
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 <suijingfeng@loongson.cn> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/vgaarb.c')
-rw-r--r--drivers/pci/vgaarb.c308
1 files changed, 159 insertions, 149 deletions
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 <benh@kernel.crashing.org>
@@ -30,22 +30,21 @@
#include <linux/vt.h>
#include <linux/console.h>
#include <linux/acpi.h>
-
#include <linux/uaccess.h>
-
#include <linux/vgaarb.h>
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 <card_ID> : switch target to card <card_ID> (see below)
- * lock <io_state> : acquires locks on target ("none" is invalid io_state)
+ * lock <io_state> : acquire locks on target ("none" is invalid io_state)
* trylock <io_state> : non-blocking acquire locks on target
* unlock <io_state> : 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,