[PATCH v2] (drm/rockchip) Reject AFBC for resolutions >2560x1600

[Andy Yan]

Hi Konstantin，

the Subject should be: drm/rockchip: xxxxxxxxxxxx

At 2025-04-14 17:53:31, "Konstantin Shabanov" <mail at etehtsea.me> wrote:
>As it isn't supported by hardware. At least, RK3399 doesn't support
>it. From the datasheet[1]
>("1.2.10 Video IN/OUT", "Display Interface", p. 17):
>
>  Support AFBC function co-operation with GPU
>    * support 2560x1600 UI
>
>Manually tested on RockPro64 (rk3399):
>- ARM_AFBC modifier is used for 1920x1080
>- DRM_FORMAT_MOD_LINEAR modifier us used for 3840x2160
>- No noise on the screen when sway is running in 4k
>- Dynamic resolution switching works correctly in sway
>
>Signed-off-by: Konstantin Shabanov <mail at etehtsea.me>
>Cc: Daniel Stone <daniel at fooishbar.org>
>Reported-by: Dan Callaghan <djc at djc.id.au>
>Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/7968
>
>[1]: https://opensource.rock-chips.com/images/d/d7/Rockchip_RK3399_Datasheet_V2.1-20200323.pdf
>---
> drivers/gpu/drm/rockchip/rockchip_drm_fb.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
>diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
>index dcc1f07632c3..1379bc3cd937 100644
>--- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
>+++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
>@@ -18,6 +18,8 @@
> #include "rockchip_drm_fb.h"
> #include "rockchip_drm_gem.h"
>
>+#define ROCKCHIP_AFBC_MAX_WIDTH		2560
>+
> static const struct drm_framebuffer_funcs rockchip_drm_fb_funcs = {
> 	.destroy       = drm_gem_fb_destroy,
> 	.create_handle = drm_gem_fb_create_handle,
>@@ -52,6 +54,13 @@ rockchip_fb_create(struct drm_device *dev, struct drm_file *file,
> 	}
>
> 	if (drm_is_afbc(mode_cmd->modifier[0])) {
>+		if (mode_cmd->width > ROCKCHIP_AFBC_MAX_WIDTH) {
>+			DRM_DEBUG_KMS("AFBC is not supported for the width %d (max %d)\n",
>+				      mode_cmd->width,
>+				      ROCKCHIP_AFBC_MAX_WIDTH);
>+			return ERR_PTR(-EINVAL);
>+		};

As the commit message saying: This restriction only applies to rk3399.

There is no such limitation for rk356x/rk3588.
But this patch will Reject AFBC for resolutions >2560x1600 on all rockchip platforms,
so this is not right.


>+
> 		int ret, i;
>
> 		ret = drm_gem_fb_afbc_init(dev, mode_cmd, afbc_fb);
>
>base-commit: e7bb7d44c3b97aea1f0e354c6499900154ac67f2
>--
>2.48.1