From 3867497d64cec53195e9de2db1118af4610fb9fe Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Fri, 5 May 2023 13:25:42 +0200 Subject: drm/tegra: sor: Add a determine_rate hook The Tegra sor pad clock implements a mux with a set_parent hook, but doesn't provide a determine_rate implementation. This is a bit odd, since set_parent() is there to, as its name implies, change the parent of a clock. However, the most likely candidates to trigger that parent change are either the assigned-clock-parents device tree property or a call to clk_set_rate(), with determine_rate() figuring out which parent is the best suited for a given rate. The other trigger would be a call to clk_set_parent(), but it's far less used, and it doesn't look like there's any obvious user for that clock. Similarly, it doesn't look like the device tree using that clock driver uses any of the assigned-clock properties on that clock. So, the set_parent hook is effectively unused, possibly because of an oversight. However, it could also be an explicit decision by the original author to avoid any reparenting but through an explicit call to clk_set_parent(). The latter case would be equivalent to setting the determine_rate implementation to clk_hw_determine_rate_no_reparent(). Indeed, if no determine_rate implementation is provided, clk_round_rate() (through clk_core_round_rate_nolock()) will call itself on the parent if CLK_SET_RATE_PARENT is set, and will not change the clock rate otherwise. And if it was an oversight, then we are at least explicit about our behavior now and it can be further refined down the line. Cc: Daniel Vetter Cc: David Airlie Cc: Jonathan Hunter Cc: Mikko Perttunen Cc: Thierry Reding Cc: dri-devel@lists.freedesktop.org Cc: linux-tegra@vger.kernel.org Signed-off-by: Maxime Ripard Link: https://lore.kernel.org/r/20221018-clk-range-checks-fixes-v4-40-971d5077e7d2@cerno.tech Signed-off-by: Stephen Boyd --- drivers/gpu/drm/tegra/sor.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/gpu/drm/tegra') diff --git a/drivers/gpu/drm/tegra/sor.c b/drivers/gpu/drm/tegra/sor.c index fbb63d755496..abd6e3b92293 100644 --- a/drivers/gpu/drm/tegra/sor.c +++ b/drivers/gpu/drm/tegra/sor.c @@ -586,6 +586,7 @@ static u8 tegra_clk_sor_pad_get_parent(struct clk_hw *hw) } static const struct clk_ops tegra_clk_sor_pad_ops = { + .determine_rate = clk_hw_determine_rate_no_reparent, .set_parent = tegra_clk_sor_pad_set_parent, .get_parent = tegra_clk_sor_pad_get_parent, }; -- cgit v1.2.3 From 27655b9bb9f0d9c32b8de8bec649b676898c52d5 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Mon, 10 Jul 2023 11:10:17 +0200 Subject: drm/client: Send hotplug event after registering a client MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Generate a hotplug event after registering a client to allow the client to configure its display. Remove the hotplug calls from the existing clients for fbdev emulation. This change fixes a concurrency bug between registering a client and receiving events from the DRM core. The bug is present in the fbdev emulation of all drivers. The fbdev emulation currently generates a hotplug event before registering the client to the device. For each new output, the DRM core sends an additional hotplug event to each registered client. If the DRM core detects first output between sending the artificial hotplug and registering the device, the output's hotplug event gets lost. If this is the first output, the fbdev console display remains dark. This has been observed with amdgpu and fbdev-generic. Fix this by adding hotplug generation directly to the client's register helper drm_client_register(). Registering the client and receiving events are serialized by struct drm_device.clientlist_mutex. So an output is either configured by the initial hotplug event, or the client has already been registered. The bug was originally added in commit 6e3f17ee73f7 ("drm/fb-helper: generic: Call drm_client_add() after setup is done"), in which adding a client and receiving a hotplug event switched order. It was hidden, as most hardware and drivers have at least on static output configured. Other drivers didn't use the internal DRM client or still had struct drm_mode_config_funcs.output_poll_changed set. That callback handled hotplug events as well. After not setting the callback in amdgpu in commit 0e3172bac3f4 ("drm/amdgpu: Don't set struct drm_driver.output_poll_changed"), amdgpu did not show a framebuffer console if output events got lost. The bug got copy-pasted from fbdev-generic into the other fbdev emulation. Reported-by: Moritz Duge Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2649 Fixes: 6e3f17ee73f7 ("drm/fb-helper: generic: Call drm_client_add() after setup is done") Fixes: 8ab59da26bc0 ("drm/fb-helper: Move generic fbdev emulation into separate source file") Fixes: b79fe9abd58b ("drm/fbdev-dma: Implement fbdev emulation for GEM DMA helpers") Fixes: 63c381552f69 ("drm/armada: Implement fbdev emulation as in-kernel client") Fixes: 49953b70e7d3 ("drm/exynos: Implement fbdev emulation as in-kernel client") Fixes: 8f1aaccb04b7 ("drm/gma500: Implement client-based fbdev emulation") Fixes: 940b869c2f2f ("drm/msm: Implement fbdev emulation as in-kernel client") Fixes: 9e69bcd88e45 ("drm/omapdrm: Implement fbdev emulation as in-kernel client") Fixes: e317a69fe891 ("drm/radeon: Implement client-based fbdev emulation") Fixes: 71ec16f45ef8 ("drm/tegra: Implement fbdev emulation as in-kernel client") Fixes: 0e3172bac3f4 ("drm/amdgpu: Don't set struct drm_driver.output_poll_changed") Signed-off-by: Thomas Zimmermann Tested-by: Moritz Duge Tested-by: Torsten Krah Tested-by: Paul Schyska Cc: Daniel Vetter Cc: David Airlie Cc: Noralf Trønnes Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Javier Martinez Canillas Cc: Russell King Cc: Inki Dae Cc: Seung-Woo Kim Cc: Kyungmin Park Cc: Krzysztof Kozlowski Cc: Patrik Jakobsson Cc: Rob Clark Cc: Abhinav Kumar Cc: Dmitry Baryshkov Cc: Tomi Valkeinen Cc: Alex Deucher Cc: "Christian König" Cc: "Pan, Xinhui" Cc: Thierry Reding Cc: Mikko Perttunen Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-arm-msm@vger.kernel.org Cc: freedreno@lists.freedesktop.org Cc: amd-gfx@lists.freedesktop.org Cc: linux-tegra@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: # v5.2+ Reviewed-by: Javier Martinez Canillas Reviewed-by: Dmitry Baryshkov # msm Link: https://patchwork.freedesktop.org/patch/msgid/20230710091029.27503-1-tzimmermann@suse.de --- drivers/gpu/drm/armada/armada_fbdev.c | 4 ---- drivers/gpu/drm/drm_client.c | 21 +++++++++++++++++++++ drivers/gpu/drm/drm_fbdev_dma.c | 4 ---- drivers/gpu/drm/drm_fbdev_generic.c | 4 ---- drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 4 ---- drivers/gpu/drm/gma500/fbdev.c | 4 ---- drivers/gpu/drm/msm/msm_fbdev.c | 4 ---- drivers/gpu/drm/omapdrm/omap_fbdev.c | 4 ---- drivers/gpu/drm/radeon/radeon_fbdev.c | 4 ---- drivers/gpu/drm/tegra/fbdev.c | 4 ---- 10 files changed, 21 insertions(+), 36 deletions(-) (limited to 'drivers/gpu/drm/tegra') diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c index 3943e89cc06c..e40a95e51785 100644 --- a/drivers/gpu/drm/armada/armada_fbdev.c +++ b/drivers/gpu/drm/armada/armada_fbdev.c @@ -209,10 +209,6 @@ void armada_fbdev_setup(struct drm_device *dev) goto err_drm_client_init; } - ret = armada_fbdev_client_hotplug(&fbh->client); - if (ret) - drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); - drm_client_register(&fbh->client); return; diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c index f6292ba0e6fc..037e36f2049c 100644 --- a/drivers/gpu/drm/drm_client.c +++ b/drivers/gpu/drm/drm_client.c @@ -122,13 +122,34 @@ EXPORT_SYMBOL(drm_client_init); * drm_client_register() it is no longer permissible to call drm_client_release() * directly (outside the unregister callback), instead cleanup will happen * automatically on driver unload. + * + * Registering a client generates a hotplug event that allows the client + * to set up its display from pre-existing outputs. The client must have + * initialized its state to able to handle the hotplug event successfully. */ void drm_client_register(struct drm_client_dev *client) { struct drm_device *dev = client->dev; + int ret; mutex_lock(&dev->clientlist_mutex); list_add(&client->list, &dev->clientlist); + + if (client->funcs && client->funcs->hotplug) { + /* + * Perform an initial hotplug event to pick up the + * display configuration for the client. This step + * has to be performed *after* registering the client + * in the list of clients, or a concurrent hotplug + * event might be lost; leaving the display off. + * + * Hold the clientlist_mutex as for a regular hotplug + * event. + */ + ret = client->funcs->hotplug(client); + if (ret) + drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); + } mutex_unlock(&dev->clientlist_mutex); } EXPORT_SYMBOL(drm_client_register); diff --git a/drivers/gpu/drm/drm_fbdev_dma.c b/drivers/gpu/drm/drm_fbdev_dma.c index 76aa52b38a13..f353daff65e1 100644 --- a/drivers/gpu/drm/drm_fbdev_dma.c +++ b/drivers/gpu/drm/drm_fbdev_dma.c @@ -252,10 +252,6 @@ void drm_fbdev_dma_setup(struct drm_device *dev, unsigned int preferred_bpp) goto err_drm_client_init; } - ret = drm_fbdev_dma_client_hotplug(&fb_helper->client); - if (ret) - drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); - drm_client_register(&fb_helper->client); return; diff --git a/drivers/gpu/drm/drm_fbdev_generic.c b/drivers/gpu/drm/drm_fbdev_generic.c index 98ae703848a0..b9343fb6cf13 100644 --- a/drivers/gpu/drm/drm_fbdev_generic.c +++ b/drivers/gpu/drm/drm_fbdev_generic.c @@ -339,10 +339,6 @@ void drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp) goto err_drm_client_init; } - ret = drm_fbdev_generic_client_hotplug(&fb_helper->client); - if (ret) - drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); - drm_client_register(&fb_helper->client); return; diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c index fdf65587f1fe..226310c765d8 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c @@ -215,10 +215,6 @@ void exynos_drm_fbdev_setup(struct drm_device *dev) if (ret) goto err_drm_client_init; - ret = exynos_drm_fbdev_client_hotplug(&fb_helper->client); - if (ret) - drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); - drm_client_register(&fb_helper->client); return; diff --git a/drivers/gpu/drm/gma500/fbdev.c b/drivers/gpu/drm/gma500/fbdev.c index 955cbe9f05a7..054426549fc6 100644 --- a/drivers/gpu/drm/gma500/fbdev.c +++ b/drivers/gpu/drm/gma500/fbdev.c @@ -328,10 +328,6 @@ void psb_fbdev_setup(struct drm_psb_private *dev_priv) goto err_drm_fb_helper_unprepare; } - ret = psb_fbdev_client_hotplug(&fb_helper->client); - if (ret) - drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); - drm_client_register(&fb_helper->client); return; diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c index b933a85420f6..bf1e17dc4550 100644 --- a/drivers/gpu/drm/msm/msm_fbdev.c +++ b/drivers/gpu/drm/msm/msm_fbdev.c @@ -246,10 +246,6 @@ void msm_fbdev_setup(struct drm_device *dev) goto err_drm_fb_helper_unprepare; } - ret = msm_fbdev_client_hotplug(&helper->client); - if (ret) - drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); - drm_client_register(&helper->client); return; diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c index b7ccce0704a3..fe6639c1cdf3 100644 --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c @@ -318,10 +318,6 @@ void omap_fbdev_setup(struct drm_device *dev) INIT_WORK(&fbdev->work, pan_worker); - ret = omap_fbdev_client_hotplug(&helper->client); - if (ret) - drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); - drm_client_register(&helper->client); return; diff --git a/drivers/gpu/drm/radeon/radeon_fbdev.c b/drivers/gpu/drm/radeon/radeon_fbdev.c index ab9c1abbac97..f941e2e7cae6 100644 --- a/drivers/gpu/drm/radeon/radeon_fbdev.c +++ b/drivers/gpu/drm/radeon/radeon_fbdev.c @@ -383,10 +383,6 @@ void radeon_fbdev_setup(struct radeon_device *rdev) goto err_drm_client_init; } - ret = radeon_fbdev_client_hotplug(&fb_helper->client); - if (ret) - drm_dbg_kms(rdev->ddev, "client hotplug ret=%d\n", ret); - drm_client_register(&fb_helper->client); return; diff --git a/drivers/gpu/drm/tegra/fbdev.c b/drivers/gpu/drm/tegra/fbdev.c index e74d9be981c7..d042234e1807 100644 --- a/drivers/gpu/drm/tegra/fbdev.c +++ b/drivers/gpu/drm/tegra/fbdev.c @@ -225,10 +225,6 @@ void tegra_fbdev_setup(struct drm_device *dev) if (ret) goto err_drm_client_init; - ret = tegra_fbdev_client_hotplug(&helper->client); - if (ret) - drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); - drm_client_register(&helper->client); return; -- cgit v1.2.3