[PATCH v2] drm/mediatek: Add valid modifier check

[Chen-Yu Tsai]

On Thu, Jul 27, 2023 at 11:04 AM CK Hu (胡俊光) <ck.hu at mediatek.com> wrote:
>
> Hi, Justin:
>
> On Wed, 2023-07-26 at 15:52 -0400, Justin Green wrote:
> >
> > External email : Please do not click links or open attachments until
> > you have verified the sender or the content.
> >  Add a check to mtk_drm_mode_fb_create() that rejects any modifier
> > that
> > is not the AFBC mode supported by MT8195's display overlays.
> >
> > Tested by booting ChromeOS and verifying the UI works, and by running
> > the ChromeOS kms_addfb_basic binary, which has a test called
> > "addfb25-bad-modifier" that attempts to create a framebuffer with the
> > modifier DRM_FORMAT_MOD_INVALID and verifies the ADDFB2 ioctl returns
> > EINVAL.
>
> Reviewed-by: CK Hu <ck.hu at mediatek.com>
>
> >
> > Signed-off-by: Justin Green <greenjustin at chromium.org>
> > Tested-by: Fei Shao <fshao at chromium.org>


Reviewed-by: Chen-Yu Tsai <wenst at chromium.org>
Tested-by: Chen-Yu Tsai <wenst at chromium.org>

with IGT on Hayato with this patch backported to v6.1 downstream kernel.

> > ---
> > v2:
> >  * Replace zero check with comparison to DRM_FORMAT_MOD_LINEAR.
> >
> >  drivers/gpu/drm/mediatek/mtk_drm_drv.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> > index cd5b18ef7951..2719a1e3163a 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> > @@ -51,6 +51,13 @@ mtk_drm_mode_fb_create(struct drm_device *dev,
> >       if (info->num_planes != 1)
> >               return ERR_PTR(-EINVAL);
> >
> > +     if (cmd->modifier[0] != DRM_FORMAT_MOD_LINEAR &&
> > +         cmd->modifier[0] != DRM_FORMAT_MOD_ARM_AFBC(
> > +                                     AFBC_FORMAT_MOD_BLOCK_SIZE_32x8
> > |
> > +                                     AFBC_FORMAT_MOD_SPLIT |
> > +                                     AFBC_FORMAT_MOD_SPARSE))
> > +             return ERR_PTR(-EINVAL);
> > +
> >       return drm_gem_fb_create(dev, file, cmd);
> >  }
> >
> > --
> > 2.41.0.487.g6d72f3e995-goog