[PATCH v9 0/9] drm/panic: Add a drm panic handler

[Sui Jingfeng]

Hi,


On 2024/3/7 17:14, 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, 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

Yes, the whole series works for me! I have tested with drm/loongson,
Are you willing to add a implement for drm/loongson driver?
If you do please add the fallowing code snippet info drm/loongson/lsdc_plane.c.
Thanks you.


static int
lsdc_primary_plane_get_scanout_buffer(struct drm_plane *plane,
                       struct drm_scanout_buffer *scanout)
{
     struct drm_framebuffer *fb;

     if (!plane->state || !plane->state->fb)
         return -ENODEV;

     fb = plane->state->fb;
     if (fb->modifier != DRM_FORMAT_MOD_LINEAR)
         return -ENODEV;

     scanout->format = fb->format;
     scanout->width = fb->width;
     scanout->height = fb->height;
     scanout->pitch = fb->pitches[0];

     return drm_gem_vmap_unlocked(fb->obj[0], &scanout->map);
}

hook this lsdc_primary_plane_get_scanout_buffer() up to the .get_scanout_buffer
member of lsdc_primary_helper_funcs, and include the #include <drm/drm_panic.h>
Thanks you in advance!