On Friday, November 3, 2023 10:53:24 AM EST Jocelyn Falempe wrote: > 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. > > This is a proof of concept, and works with simpledrm and mgag200, using a new get_scanout_buffer() api > > To test it, make sure you're using the simpledrm driver, and trigger a panic: > echo c > /proc/sysrq-trigger > > 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) > > > With mgag200 support, I was able to test that the xrgb8888 to rgb565 conversion is working. > I am unable to test with that hardware, but I am able to test with simpledrm, and it works pretty good > IMX/IPUV3 support is not complete, I wasn't able to have etnaviv working on my board. > But it shows that it can still work on ARM with DMA buffer in this case. > > Best regards, > > > Jocelyn Falempe (6): > drm/format-helper: Add drm_fb_blit_from_r1 and drm_fb_fill > drm/panic: Add a drm panic handler > drm/simpledrm: Add drm_panic support > drm/mgag200: Add drm_panic support > drm/ast: Add drm_panic support > drm/imx: Add drm_panic support > > drivers/gpu/drm/Kconfig | 22 ++ > drivers/gpu/drm/Makefile | 1 + > drivers/gpu/drm/ast/ast_drv.c | 4 +- > drivers/gpu/drm/ast/ast_drv.h | 3 + > drivers/gpu/drm/ast/ast_mode.c | 26 ++ > drivers/gpu/drm/drm_drv.c | 8 + > drivers/gpu/drm/drm_format_helper.c | 421 ++++++++++++++++++----- > drivers/gpu/drm/drm_panic.c | 368 ++++++++++++++++++++ > drivers/gpu/drm/imx/ipuv3/imx-drm-core.c | 30 ++ > drivers/gpu/drm/mgag200/mgag200_drv.c | 25 ++ > drivers/gpu/drm/tiny/simpledrm.c | 15 + > include/drm/drm_drv.h | 21 ++ > include/drm/drm_format_helper.h | 9 + > include/drm/drm_panic.h | 96 ++++++ > 14 files changed, 966 insertions(+), 83 deletions(-) > create mode 100644 drivers/gpu/drm/drm_panic.c > create mode 100644 include/drm/drm_panic.h > > > base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa >
