kernel/linux.git/drivers/gpu/drm/drm_fbdev_dma.c, branch v6.4.15

drm/client: Send hotplug event after registering a client

2023-07-23T11:53:50+00:00

commit 27655b9bb9f0d9c32b8de8bec649b676898c52d5 upstream. 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 [ Dropped changes to drivers/gpu/drm/armada/armada_fbdev.c as 174c3c38e3a2 drm/armada: Initialize fbdev DRM client was introduced in 6.5-rc1 ] Signed-off-by: Mario Limonciello Signed-off-by: Greg Kroah-Hartman

drm/fbdev-dma: Fix documented default preferred_bpp value

2023-07-23T11:53:41+00:00

[ Upstream commit 15008052b34efaa86c1d56190ac73c4bf8c462f9 ] As of commit 6c80a93be62d398e ("drm/fb-helper: Initialize fb-helper's preferred BPP in prepare function"), the preferred_bpp parameter of drm_fb_helper_prepare() defaults to 32 instead of drm_mode_config.preferred_depth. Hence this also applies to drm_fbdev_dma_setup(), which just passes its own preferred_bpp parameter. Fixes: b79fe9abd58bab73 ("drm/fbdev-dma: Implement fbdev emulation for GEM DMA helpers") Signed-off-by: Geert Uytterhoeven Reviewed-by: Thomas Zimmermann Signed-off-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/91f093ffe436a9f94d58fb2bfbc1407f1ebe8bb0.1688656591.git.geert+renesas@glider.be Signed-off-by: Sasha Levin

drm/fb-helper: Consolidate CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM

2023-03-22T12:32:52+00:00

Consolidate all handling of CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM by making the module parameter optional in drm_fb_helper.c. Without the config option, modules can set smem_start in struct fb_info for internal usage, but not export if to userspace. The address can only be exported by enabling the option and setting the module parameter. Also update the comment. Signed-off-by: Thomas Zimmermann Reviewed-by: Javier Martinez Canillas Acked-by: Zack Rusin Tested-by: Sui Jingfeng Link: https://patchwork.freedesktop.org/patch/msgid/20230320150751.20399-8-tzimmermann@suse.de

drm/fbdev-dma: Implement fbdev emulation for GEM DMA helpers

2023-03-14T16:07:47+00:00

Implement fbdev emulation that is optimized for drivers that use DMA helpers. The buffers may no tbe moveable, may not require damage handling and have to be located in system memory. This allows fbdev emulation to operate directly on the buffer and mmap it to userspace. Besides those constraints, the emulation works like in the generic code. As an internal DRM client provides, it receives hotplug, restore and unregister events. The DRM client is independent from the fbdev probing, which runs on the first successful hotplug event. The emulation is part of the DMA helper module and not build unless DMA helpers and fbdev emulation has been configured. Tested with vc4. Signed-off-by: Thomas Zimmermann Reviewed-by: Javier Martinez Canillas Link: https://patchwork.freedesktop.org/patch/msgid/20230313155138.20584-2-tzimmermann@suse.de