Hi

On 20.10.20 10:35, Daniel Vetter wrote:

There's a confusion between the preferred_depth uapi and the generic fbdev helpers. Former wants depth, latter wants bpp, and for XRGB8888 they don't match. Which hit me with vkms, which wants that.

All other drivers setting this and using the generic fbdev helpers use 16, where both numbers match, for RGB565.

Since fixing this is a bit involved (I think for atomic drivers we should just compute this all internally from the format list of the first primary plane) paper over the issue in vkms by using defaults everywhere. Then userspace will pick XRGB8888, and fbdev helpers will do the same, and we have what we want.

Reported-by: Simon Ser contact@emersion.fr Cc: Simon Ser contact@emersion.fr Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: Rodrigo Siqueira rodrigosiqueiramelo@gmail.com Cc: Melissa Wen melissa.srw@gmail.com Cc: Haneen Mohammed hamohammed.sa@gmail.com Cc: Daniel Vetter daniel@ffwll.ch

---

drivers/gpu/drm/vkms/vkms_drv.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c index 25faba5aac08..98ba844ae77d 100644 --- a/drivers/gpu/drm/vkms/vkms_drv.c +++ b/drivers/gpu/drm/vkms/vkms_drv.c @@ -114,7 +114,10 @@ static int vkms_modeset_init(struct vkms_device *vkmsdev) dev->mode_config.max_height = YRES_MAX; dev->mode_config.cursor_width = 512; dev->mode_config.cursor_height = 512;

• dev->mode_config.preferred_depth = 32;

• /* FIXME: There's a confusion between bpp and depth between this and

• * fbdev helpers. We have to go with 0, meaning "pick the default",
  

• * which ix XRGB8888 in all cases. */
  

• dev->mode_config.preferred_depth = 0;

It's already 0 at this point.

I suggest to rather document this FIXME as part of the documentation of drm_fbdev_generic_setup() and preferred_depth. Other drivers are also affected.

Best regards Thomas

dev->mode_config.helper_private = &vkms_mode_config_helpers;

return vkms_output_init(vkmsdev, 0);