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path: root/drivers/gpu/drm/tegra/fbdev.c
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2023-07-11drm/client: Send hotplug event after registering a clientThomas Zimmermann
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 <MoritzDuge@kolahilft.de> 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 <tzimmermann@suse.de> Tested-by: Moritz Duge <MoritzDuge@kolahilft.de> Tested-by: Torsten Krah <krah.tm@gmail.com> Tested-by: Paul Schyska <pschyska@gmail.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Airlie <airlied@gmail.com> Cc: Noralf Trønnes <noralf@tronnes.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Javier Martinez Canillas <javierm@redhat.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Inki Dae <inki.dae@samsung.com> Cc: Seung-Woo Kim <sw0312.kim@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com> Cc: Rob Clark <robdclark@gmail.com> Cc: Abhinav Kumar <quic_abhinavk@quicinc.com> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Cc: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: "Christian König" <christian.koenig@amd.com> Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Mikko Perttunen <mperttunen@nvidia.com> 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: <stable@vger.kernel.org> # v5.2+ Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> # msm Link: https://patchwork.freedesktop.org/patch/msgid/20230710091029.27503-1-tzimmermann@suse.de
2023-06-01drm/tegra: Use regular fbdev I/O helpersThomas Zimmermann
Use the regular fbdev helpers for framebuffer I/O instead of DRM's helpers. Tegra does not use damage handling, so DRM's fbdev helpers are mere wrappers around the fbdev code. By using fbdev helpers directly within each DRM fbdev emulation, we can eventually remove DRM's wrapper functions entirely. v4: * use initializer macros for struct fb_ops v2: * use FB_SYS_HELPERS option Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Acked-by: Sam Ravnborg <sam@ravnborg.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Mikko Perttunen <mperttunen@nvidia.com> Cc: Jonathan Hunter <jonathanh@nvidia.com> Acked-by: Thierry Reding <treding@nvidia.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230530151228.22979-10-tzimmermann@suse.de
2023-04-06drm/tegra: Implement fbdev emulation as in-kernel clientThomas Zimmermann
Move code from ad-hoc fbdev callbacks into DRM client functions and remove the old callbacks. The functions instruct the client to poll for changed output or restore the display. The DRM core calls both, the old callbacks and the new client helpers, from the same places. The new functions perform the same operation as before, so there's no change in functionality. Replace all code that initializes or releases fbdev emulation throughout the driver. Instead initialize the fbdev client by a single call to tegra_fbdev_setup() after tegra has registered its DRM device. As in most drivers, tegra's fbdev emulation now acts like a regular DRM client. The fbdev client setup consists of the initial preparation and the hot-plugging of the display. The latter creates the fbdev device and sets up the fbdev framebuffer. The setup performs display hot-plugging once. If no display can be detected, DRM probe helpers re-run the detection on each hotplug event. A call to drm_dev_unregister() releases the client automatically. No further action is required within tegra. If the fbdev framebuffer has been fully set up, struct fb_ops.fb_destroy implements the release. For partially initialized emulation, the fbdev client reverts the initial setup. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Thierry Reding <treding@nvidia.com>
2023-04-06drm/tegra: Initialize fbdev DRM clientThomas Zimmermann
Initialize the fbdev client in the fbdev code with empty helper functions. Also clean up the client. The helpers will later implement various functionality of the DRM client. No functional changes. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Thierry Reding <treding@nvidia.com>
2023-04-06drm/tegra: Hide fbdev support behind config optionThomas Zimmermann
Only build tegra's fbdev emulation if CONFIG_DRM_FBDEV_EMULATION has been enabled. As part of this change, move the code into its own source file. No functional changes. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Thierry Reding <treding@nvidia.com>