On Tue, Apr 09, 2024 at 06:30:39PM +0200, Jocelyn Falempe wrote: > drm/panic: Add a drm panic handler > > This introduces a new drm panic handler, which displays a message when a panic occurs. > So when fbcon is disabled, you can still see a kernel panic. > > This is one of the missing feature, when disabling VT/fbcon in the kernel: > https://www.reddit.com/r/linux/comments/10eccv9/config_vtn_in_2023/ > Fbcon can be replaced by a userspace kms console, but the panic screen must be done in the kernel. > > It works with simpledrm, mgag200, ast, and imx. > > To test it, make sure you're using one of the supported driver, and trigger a panic: > echo c > /proc/sysrq-trigger > > or you can enable CONFIG_DRM_PANIC_DEBUG and echo 1 > /sys/kernel/debug/dri/0/drm_panic_plane_0 > > Even if this is not yet useful, it will allows to work on more driver support, and better debug information to be added. > > v2: > * Use get_scanout_buffer() instead of the drm client API. (Thomas Zimmermann) > * Add the panic reason to the panic message (Nerdopolis) > * Add an exclamation mark (Nerdopolis) > > v3: > * Rework the drawing functions, to write the pixels line by line and > to use the drm conversion helper to support other formats. > (Thomas Zimmermann) > > v4: > * Fully support all simpledrm formats using drm conversion helpers > * Rename dpanic_* to drm_panic_*, and have more coherent function name. > (Thomas Zimmermann) > * Use drm_fb_r1_to_32bit for fonts (Thomas Zimmermann) > * Remove the default y to DRM_PANIC config option (Thomas Zimmermann) > * Add foreground/background color config option > * Fix the bottom lines not painted if the framebuffer height > is not a multiple of the font height. > * Automatically register the driver to drm_panic, if the function > get_scanout_buffer() exists. (Thomas Zimmermann) > * Add mgag200 support. > > v5: > * Change the drawing API, use drm_fb_blit_from_r1() to draw the font. > (Thomas Zimmermann) > * Also add drm_fb_fill() to fill area with background color. > * Add draw_pixel_xy() API for drivers that can't provide a linear buffer. > * Add a flush() callback for drivers that needs to synchronize the buffer. > * Add a void *private field, so drivers can pass private data to > draw_pixel_xy() and flush(). > * Add ast support. > * Add experimental imx/ipuv3 support, to test on an ARM hw. (Maxime Ripard) > > v6: > * Fix sparse and __le32 warnings > * Drop the IMX/IPUV3 experiment, it was just to show that it works also on > ARM devices. > > v7: > * Add a check to see if the 4cc format is supported by drm_panic. > * Add a drm/plane helper to loop over all visible primary buffer, > simplifying the get_scanout_buffer implementations > * Add a generic implementation for drivers that uses drm_fb_dma. (Maxime Ripard) > * Add back the IMX/IPUV3 support, and use the generic implementation. (Maxime Ripard) > > v8: > * Directly register each plane to the panic notifier (Sima) > * Replace get_scanout_buffer() with set_scanout_buffer() to simplify > the locking. (Thomas Zimmermann) > * Add a debugfs entry, to trigger the drm_panic without a real panic (Sima) > * Fix the drm_panic Documentation, and include it in drm-kms.rst > > v9: > * Revert to using get_scanout_buffer() (Sima) > * Move get_scanout_buffer() and panic_flush() to the plane helper > functions (Thomas Zimmermann) > * Register all planes with get_scanout_buffer() to the panic notifier > * Use drm_panic_lock() to protect against race (Sima) > * Create a debugfs file for each plane in the device's debugfs > directory. This allows to test for each plane of each GPU > independently. > v10: > * Move blit and fill functions back in drm_panic (Thomas Zimmermann). > * Simplify the text drawing functions. > * Use kmsg_dumper instead of panic_notifier (Sima). > * Use spinlock_irqsave/restore (John Ogness) > > v11: > * Use macro instead of inline functions for drm_panic_lock/unlock (John Ogness) > > v12: > * Use array for map and pitch in struct drm_scanout_buffer > to support multi-planar format later. (Thomas Zimmermann) > * Rename drm_panic_gem_get_scanout_buffer to drm_fb_dma_get_scanout_buffer > and build it unconditionally (Thomas Zimmermann) > * Better indent struct drm_scanout_buffer declaration. (Thomas Zimmermann) On the series: Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx> And apologies for the detours this patch set took and my part in the (too many) revisions. I think we should land this and do anything more once it's merged and we extend the panic support to more drivers. Thanks a lot to you for seeing this through! Cheers, Sima > > > Best regards, > > > Daniel Vetter (1): > drm/panic: Add drm panic locking > > Jocelyn Falempe (8): > drm/panic: Add a drm panic handler > drm/panic: Add support for color format conversion > drm/panic: Add debugfs entry to test without triggering panic. > drm/fb_dma: Add generic get_scanout_buffer() for drm_panic > drm/simpledrm: Add drm_panic support > drm/mgag200: Add drm_panic support > drm/imx: Add drm_panic support > drm/ast: Add drm_panic support > > Documentation/gpu/drm-kms.rst | 12 + > drivers/gpu/drm/Kconfig | 32 ++ > drivers/gpu/drm/Makefile | 1 + > drivers/gpu/drm/ast/ast_mode.c | 18 + > drivers/gpu/drm/drm_atomic_helper.c | 4 + > drivers/gpu/drm/drm_drv.c | 5 + > drivers/gpu/drm/drm_fb_dma_helper.c | 42 ++ > drivers/gpu/drm/drm_panic.c | 583 +++++++++++++++++++++++ > drivers/gpu/drm/imx/ipuv3/ipuv3-plane.c | 11 +- > drivers/gpu/drm/mgag200/mgag200_drv.h | 7 +- > drivers/gpu/drm/mgag200/mgag200_mode.c | 18 + > drivers/gpu/drm/tiny/simpledrm.c | 16 + > include/drm/drm_fb_dma_helper.h | 4 + > include/drm/drm_mode_config.h | 10 + > include/drm/drm_modeset_helper_vtables.h | 37 ++ > include/drm/drm_panic.h | 157 ++++++ > include/drm/drm_plane.h | 6 + > 17 files changed, 961 insertions(+), 2 deletions(-) > create mode 100644 drivers/gpu/drm/drm_panic.c > create mode 100644 include/drm/drm_panic.h > > > base-commit: 935a92a1c400285545198ca2800a4c6c519c650a > -- > 2.44.0 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
