On 3/3/22 21:58, Thomas Zimmermann wrote:
> Implement struct drm_driver.dumb_create_fbdev with the helpers
> provided by GEM SHMEM. Fbdev deferred I/O will now work without
> an intermediate shadow buffer for mmap.
>
> As the virtio driver replaces several of the regular GEM SHMEM
> functions with its own implementation, some additional code is
> necessary make fbdev optimization work. Especially, the driver
> has to provide buffer-object functions for fbdev. Add the hook
> struct drm_driver.gem_create_object_fbdev, which is similar to
> struct drm_driver.gem_create_object and allows for the creation
> of dedicated fbdev buffer objects. Wire things up within GEM
> SHMEM.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> ---
> drivers/gpu/drm/drm_gem_shmem_helper.c | 7 +++-
> drivers/gpu/drm/virtio/virtgpu_drv.c | 2 +
> drivers/gpu/drm/virtio/virtgpu_drv.h | 2 +
> drivers/gpu/drm/virtio/virtgpu_object.c | 54 +++++++++++++++++++++++--
> include/drm/drm_drv.h | 10 +++++
> 5 files changed, 71 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
> index ab7cb7d896c3..225aa17895bd 100644
> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> @@ -71,7 +71,12 @@ __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private, bool f
>
> size = PAGE_ALIGN(size);
>
> - if (dev->driver->gem_create_object) {
> + if (dev->driver->gem_create_object_fbdev && fbdev) {
Same comment here to check if fbdev emulation is enabled or maybe is not
worht it ? But I think this hints the compiler to optimize the if branch.
[snip]
> +}
> +#else
> +struct drm_gem_object *virtio_gpu_create_object_fbdev(struct drm_device *dev,
> + size_t size)
> +{
> + return ERR_PTR(-ENOSYS);
> +}
As mentioned, I believe this should be ERR_PTR(-ENOTSUPP) instead.
Feel free to ignore all this nits if you consider that are not applicable.
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
--
Best regards,
Javier Martinez Canillas
Linux Engineering
Red Hat
