On 3/13/24 10:44, Louis Chauvet wrote: > Introduce two callbacks which does nothing. They are used in replacement > of NULL and it avoid kernel OOPS if this NULL is called. > > If those callback are used, it means that there is a mismatch between > what formats are announced by atomic_check and what is realy supported by > atomic_update. > > Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx> > --- > drivers/gpu/drm/vkms/vkms_formats.c | 43 +++++++++++++++++++++++++++++++------ > 1 file changed, 37 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c > index 55a4365d21a4..b57d85b8b935 100644 > --- a/drivers/gpu/drm/vkms/vkms_formats.c > +++ b/drivers/gpu/drm/vkms/vkms_formats.c > @@ -261,8 +286,8 @@ void vkms_writeback_row(struct vkms_writeback_job *wb, > > /** Please mak this comment conform to kernel-doc format or don't use "/**" to begin the comment. > * Retrieve the correct read_pixel function for a specific format. > - * The returned pointer is NULL for unsupported pixel formats. The caller must ensure that the > - * pointer is valid before using it in a vkms_plane_state. > + * If the format is not supported by VKMS a warn is emitted and a dummy "always read black" > + * function is returned. > * > * @format: DRM_FORMAT_* value for which to obtain a conversion function (see [drm_fourcc.h]) > */ > @@ -285,18 +310,21 @@ pixel_read_t get_pixel_read_function(u32 format) > * format must: > * - Be listed in vkms_formats in vkms_plane.c > * - Have a pixel_read callback defined here > + * > + * To avoid kernel crash, a dummy "always read black" function is used. It means > + * that during the composition, this plane will always be black. > */ > WARN(true, > "Pixel format %p4cc is not supported by VKMS planes. This is a kernel bug, atomic check must forbid this configuration.\n", > &format); > - return (pixel_read_t)NULL; > + return &black_to_argb_u16; > } > } > > /** Same here. > * Retrieve the correct write_pixel function for a specific format. > - * The returned pointer is NULL for unsupported pixel formats. The caller must ensure that the > - * pointer is valid before using it in a vkms_writeback_job. > + * If the format is not supported by VKMS a warn is emitted and a dummy "don't do anything" > + * function is returned. > * > * @format: DRM_FORMAT_* value for which to obtain a conversion function (see [drm_fourcc.h]) > */ thanks. -- #Randy
