On Fri, Oct 08, 2021 at 02:02:40PM +0300, Ville Syrjälä wrote:
On Fri, Oct 08, 2021 at 09:17:08AM +0200, Javier Martinez Canillas wrote:
This reverts commit b3484d2b03e4c940a9598aa841a52d69729c582a.
That change attempted to improve the DRM drivers fbdev emulation device names to avoid having confusing names like "simpledrmdrmfb" in /proc/fb.
But unfortunately there are user-space programs, such as pm-utils that query that information and so broke after the mentioned commit. Since the names in /proc/fb are used programs that consider it an ABI, let's restore the old names even when this lead to silly naming like the one mentioned above as an example.
The usage Johannes listed was this specificially: using_kms() { grep -q -E '(nouveau|drm)fb' /proc/fb; }
So it actually looks like Daniel's commit f243dd06180a ("drm/nouveau: Use drm_fb_helper_fill_info") also broke the abi. But for the pm-utils use case at least just having the "drmfb" in there should cover even nouveau.
Cc: stable@vger.kernel.org Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com
Reported-by: Johannes Stezenbach js@sig21.net Signed-off-by: Javier Martinez Canillas javierm@redhat.com
drivers/gpu/drm/drm_fb_helper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 3ab07832104..8993b02e783 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -1737,7 +1737,7 @@ void drm_fb_helper_fill_info(struct fb_info *info, sizes->fb_width, sizes->fb_height);
info->par = fb_helper;
- snprintf(info->fix.id, sizeof(info->fix.id), "%s",
Please add a comment here that drmfb is uapi because pm-utils matches against it ...
Otherwise this will be lost in time again :-( -Daniel
- snprintf(info->fix.id, sizeof(info->fix.id), "%sdrmfb", fb_helper->dev->driver->name);
}
2.31.1
-- Ville Syrjälä Intel