Re: [PATCH 2/2] drm/panic: Accept a trailing newline in panic_screen

[Tvrtko Ursulin]

On 16/10/2026 06:27, Devin Wittmayer wrote:
Setting the panic screen through sysfs with echo fails with EINVAL,
because the value ends in a newline. Ignore it when matching.

Fixes: e85e9ccf3f84 ("drm/panic: Report invalid or unsupported panic modes")
Signed-off-by: Devin Wittmayer <lucid_d...@justthetip.ca>
---
QEMU, 10 runs each, on drm-misc-fixes and drm-misc-next:

                                      before    after
   write of "user\n"                  refused   takes
   write of "bsod\n"                  refused   refused

Hah funny, becuase before e85e9ccf3f84 it used to take "bsod\n" but 
AFAIR it would silently revert to displaying "user". Because old code 
was this:

static void draw_panic_dispatch(struct drm_scanout_buffer *sb)
{
       if (!strcmp(drm_panic_screen, "kmsg")) {
               draw_panic_static_kmsg(sb);
       } else if (!strcmp(drm_panic_screen, "qr_code")) {
               draw_panic_static_qr_code(sb);
       } else {
               draw_panic_static_user(sb);
       }
}

But it is true that it would also silently accept "user\n" so I guess 
you can call it a partial regression.

Anyway, the fix LGTM.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursu...@igalia.com>

Regards,

Tvrtko

   drm.panic_screen=user at boot      takes     takes

amdgpu, 2 runs each, 7.2.6 with Arch's source and config:

   echo user                          refused   takes

  drivers/gpu/drm/drm_panic.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index 29b1487de7ae0..7847b38ba9aab 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -839,7 +839,7 @@ static int drm_panic_type_set(const char *val, const struct 
kernel_param *kp)
        unsigned int i;
  
  	for (i = 0; i < ARRAY_SIZE(drm_panic_type_map); i++) {
-               if (!strcmp(val, drm_panic_type_map[i])) {
+               if (sysfs_streq(val, drm_panic_type_map[i])) {
                        drm_panic_type = i;
                        return 0;
                }