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References: <20220113094419.12433-1-etom@igel.co.jp>
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From:   Daniel Stone <daniel@fooishbar.org>
Date:   Thu, 13 Jan 2022 13:44:18 +0000
Message-ID: <CAPj87rPk3_8LdnwWJ3BhtJnRuR+_WHg2hfdgK2R4SMacPGCrUQ@mail.gmail.com>
Subject: Re: [RFC PATCH v2 0/3] Add support modifiers for drivers whose planes
 only support linear layout
To:     Tomohito Esaki <etom@igel.co.jp>
Cc:     dri-devel@lists.freedesktop.org,
        Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Ben Skeggs <bskeggs@redhat.com>,
        =?UTF-8?Q?Michel_D=C3=A4nzer?= <mdaenzer@redhat.com>,
        Simon Ser <contact@emersion.fr>,
        Qingqing Zhuo <qingqing.zhuo@amd.com>,
        Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>,
        Mark Yacoub <markyacoub@chromium.org>,
        Sean Paul <seanpaul@chromium.org>,
        Evan Quan <evan.quan@amd.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Petr Mladek <pmladek@suse.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Lee Jones <lee.jones@linaro.org>,
        Abhinav Kumar <abhinavk@codeaurora.org>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Rob Clark <robdclark@chromium.org>,
        amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        nouveau@lists.freedesktop.org,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Damian Hobson-Garcia <dhobsong@igel.co.jp>,
        Takanari Hayama <taki@igel.co.jp>
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Hi Esaki-san,

On Thu, 13 Jan 2022 at 09:44, Tomohito Esaki <etom@igel.co.jp> wrote:
> Some drivers whose planes only support linear layout fb do not support format
> modifiers.
> These drivers should support modifiers, however the DRM core should handle this
> rather than open-coding in every driver.
>
> In this patch series, these drivers expose format modifiers based on the
> following suggestion[1].

Thanks for the series, it looks like the right thing to do.

Can you please change the patch ordering though? At the moment there
will be a bisection break at patch #1, because the legacy drivers will
suddenly start gaining modifier support, before it is removed in patch
#2.

I think a better order would be:
  1: add fb_modifiers_not_supported flag to core and drivers
  2: add default modifiers (and set allow_fb_modifiers) if
fb_modifiers_not_supported flag is not set
  3: remove allow_fb_modifiers flag

Cheers,
Daniel