Re: [PATCH] drm/amdgpu: Ensure that the modifier requested is supported by plane.

From: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
To: Mark Yacoub <markyacoub@chromium.org>
Cc: Alex Deucher <alexander.deucher@amd.com>,
	ML dri-devel <dri-devel@lists.freedesktop.org>,
	amd-gfx mailing list <amd-gfx@lists.freedesktop.org>,
	Mark Yacoub <markyacoub@google.com>
Subject: Re: [PATCH] drm/amdgpu: Ensure that the modifier requested is supported by plane.
Date: Tue, 23 Mar 2021 16:08:07 +0100	[thread overview]
Message-ID: <CAP+8YyFb4ax0Z6Ev2=KpqF481kFyG_Br+WT=72dGK-tATXVrGg@mail.gmail.com> (raw)
In-Reply-To: <20210310161444.1015500-1-markyacoub@chromium.org>

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On Wed, Mar 10, 2021 at 5:14 PM Mark Yacoub <markyacoub@chromium.org> wrote:

> From: Mark Yacoub <markyacoub@google.com>
>
> On initializing the framebuffer, call drm_any_plane_has_format to do a
> check if the modifier is supported. drm_any_plane_has_format calls
> dm_plane_format_mod_supported which is extended to validate that the
> modifier is on the list of the plane's supported modifiers.
>
> The bug was caught using igt-gpu-tools test:
> kms_addfb_basic.addfb25-bad-modifier
>
> Tested on ChromeOS Zork by turning on the display, running an overlay
> test, and running a YT video.
>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
> Signed-off-by: default avatarMark Yacoub <markyacoub@chromium.org>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_display.c       | 13 +++++++++++++
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  9 +++++++++
>  2 files changed, 22 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> index afa5f8ad0f563..a947b5aa420d2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> @@ -908,6 +908,19 @@ int amdgpu_display_gem_fb_verify_and_init(
>                                          &amdgpu_fb_funcs);
>         if (ret)
>                 goto err;
> +       /* Verify that the modifier is supported. */
> +       if (!drm_any_plane_has_format(dev, mode_cmd->pixel_format,
> +                                     mode_cmd->modifier[0])) {
> +               struct drm_format_name_buf format_name;
> +               drm_dbg_kms(dev,
> +                           "unsupported pixel format %s / modifier
> 0x%llx\n",
> +                           drm_get_format_name(mode_cmd->pixel_format,
> +                                               &format_name),
> +                           mode_cmd->modifier[0]);
> +
> +               ret = -EINVAL;
> +               goto err;
> +       }
>

Why is this needed?

>         ret = amdgpu_display_framebuffer_init(dev, rfb, mode_cmd, obj);
>         if (ret)
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 961abf1cf040c..21314024a83ce 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -3939,6 +3939,7 @@ static bool dm_plane_format_mod_supported(struct
> drm_plane *plane,
>  {
>         struct amdgpu_device *adev = drm_to_adev(plane->dev);
>         const struct drm_format_info *info = drm_format_info(format);
> +       int i;
>
>         enum dm_micro_swizzle microtile =
> modifier_gfx9_swizzle_mode(modifier) & 3;
>
> @@ -3952,6 +3953,14 @@ static bool dm_plane_format_mod_supported(struct
> drm_plane *plane,
>         if (modifier == DRM_FORMAT_MOD_LINEAR)
>                 return true;
>
> +       /* Check that the modifier is on the list of the plane's supported
> modifiers. */
> +       for (i = 0; i < plane->modifier_count; i++) {
> +               if (modifier == plane->modifiers[i])
> +                       break;
> +       }
> +       if (i == plane->modifier_count)
> +               return false;
> +
>

This part seems fine by me.

>         /*
>          * The arbitrary tiling support for multiplane formats has not
> been hooked
>          * up.
> --
> 2.30.1.766.gb4fecdf3b7-goog
>
>

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