From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: "José Expósito" <jose.exposito89@gmail.com>
Cc: contact@emersion.fr, airlied@linux.ie,
alexandre.torgue@foss.st.com, benjamin.gaignard@linaro.org,
linux-stm32@st-md-mailman.stormreply.com, marex@denx.de,
linux-imx@nxp.com, intel-gfx@lists.freedesktop.org,
tzimmermann@suse.de, s.hauer@pengutronix.de,
rodrigo.vivi@intel.com, kernel@pengutronix.de,
linux-arm-kernel@lists.infradead.org,
dri-devel@lists.freedesktop.org, yannick.fertre@foss.st.com,
linux-kernel@vger.kernel.org, philippe.cornu@foss.st.com,
mcoquelin.stm32@gmail.com, dmitry.baryshkov@linaro.org,
shawnguo@kernel.org
Subject: Re: [PATCH v2 1/6] drm/plane: Make format_mod_supported truly optional
Date: Thu, 23 Dec 2021 13:56:55 +0200 [thread overview]
Message-ID: <YcRkB7uWyt4EbcZm@intel.com> (raw)
In-Reply-To: <20211222090552.25972-2-jose.exposito89@gmail.com>
On Wed, Dec 22, 2021 at 10:05:47AM +0100, José Expósito wrote:
> The documentation for "drm_plane_funcs.format_mod_supported" reads:
>
> This *optional* hook is used for the DRM to determine if the given
> format/modifier combination is valid for the plane. This allows the
> DRM to generate the correct format bitmask (which formats apply to
> which modifier), and to validate modifiers at atomic_check time.
>
> *If not present*, then any modifier in the plane's modifier
> list is allowed with any of the plane's formats.
>
> However, where the function is not present, an invalid IN_FORMATS blob
> property with modifiers but no formats is exposed to user-space.
>
> This breaks the latest Weston [1]. For testing purposes, I extracted the
> affected code to a standalone program [2].
>
> Make "create_in_format_blob" behave as documented.
>
> [1] https://gitlab.freedesktop.org/wayland/weston/-/blob/9.0/libweston/backend-drm/kms.c#L431
> [2] https://github.com/JoseExposito/drm-sandbox/blob/main/in_formats.c
>
> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
> ---
> drivers/gpu/drm/drm_plane.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
> index 82afb854141b..c1186b7215ee 100644
> --- a/drivers/gpu/drm/drm_plane.c
> +++ b/drivers/gpu/drm/drm_plane.c
> @@ -202,17 +202,13 @@ static int create_in_format_blob(struct drm_device *dev, struct drm_plane *plane
>
> memcpy(formats_ptr(blob_data), plane->format_types, formats_size);
>
> - /* If we can't determine support, just bail */
> - if (!plane->funcs->format_mod_supported)
> - goto done;
> -
> mod = modifiers_ptr(blob_data);
> for (i = 0; i < plane->modifier_count; i++) {
> for (j = 0; j < plane->format_count; j++) {
> - if (plane->funcs->format_mod_supported(plane,
> + if (!plane->funcs->format_mod_supported ||
> + plane->funcs->format_mod_supported(plane,
> plane->format_types[j],
> plane->modifiers[i])) {
So instead of skipping the whole loop you just skip doing anything
inside the loop? Can't see how that achieves anything at all.
https://patchwork.freedesktop.org/series/83018/
is what I had in mind earlier but no one reviewed it and
the discussion veered off track IIRC.
--
Ville Syrjälä
Intel
next prev parent reply other threads:[~2021-12-23 11:57 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-22 9:05 [PATCH v2 0/6] Add missing format_mod_supported functions José Expósito
2021-12-22 9:05 ` [PATCH v2 1/6] drm/plane: Make format_mod_supported truly optional José Expósito
2021-12-23 10:10 ` Simon Ser
2021-12-23 11:56 ` Ville Syrjälä [this message]
2021-12-23 13:42 ` Simon Ser
2021-12-23 15:03 ` Ville Syrjälä
2021-12-23 16:57 ` José Expósito
2021-12-22 9:05 ` [PATCH v2 2/6] drm/plane: Fix typo in format_mod_supported documentation José Expósito
2021-12-23 10:07 ` Simon Ser
2021-12-22 9:05 ` [PATCH v2 3/6] drm/simple-kms: Drop format_mod_supported function José Expósito
2021-12-22 9:05 ` [PATCH v2 4/6] drm/i915/display: " José Expósito
2021-12-22 9:05 ` [PATCH v2 5/6] drm: mxsfb: " José Expósito
2021-12-22 9:05 ` [PATCH v2 6/6] drm/stm: ltdc: " José Expósito
2022-01-12 9:44 ` yannick Fertre
2022-01-12 10:01 ` Jagan Teki
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