linux-kernel - Re: [PATCH v2 5/5] drm/tegra: plane: Support 180° rotation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <2a004826-a505-75e4-b922-c74618404166@gmail.com>
Date:   Wed, 17 Jun 2020 21:50:41 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Emil Velikov <emil.l.velikov@...il.com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Derek Basehore <dbasehore@...omium.org>,
        Sam Ravnborg <sam@...nborg.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Sean Paul <sean@...rly.run>, linux-tegra@...r.kernel.org,
        "Linux-Kernel@...r. Kernel. Org" <linux-kernel@...r.kernel.org>,
        ML dri-devel <dri-devel@...ts.freedesktop.org>
Subject: Re: [PATCH v2 5/5] drm/tegra: plane: Support 180° rotation

16.06.2020 14:25, Dmitry Osipenko пишет:
> 16.06.2020 00:47, Emil Velikov пишет:
>> Hi all,
>>
>> Perhaps a silly question:
>>
>> On Mon, 15 Jun 2020 at 08:28, Dmitry Osipenko <digetx@...il.com> wrote:
>>>
>>> Combining horizontal and vertical reflections gives us 180 degrees of
>>> rotation.
>>>
>>> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
>>> ---
>>>  drivers/gpu/drm/tegra/dc.c | 13 ++++++++++++-
>>>  1 file changed, 12 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
>>> index f31bca27cde4..ddd9b88f8fce 100644
>>> --- a/drivers/gpu/drm/tegra/dc.c
>>> +++ b/drivers/gpu/drm/tegra/dc.c
>>
>>> +       if (rotation & DRM_MODE_ROTATE_180) {
>>> +               plane_state->reflect_x = !plane_state->reflect_x;
>>> +               plane_state->reflect_y = !plane_state->reflect_y;
>>> +       }
>>> +
>> As mentioned by Ville the above is already handled by
>> drm_rotation_simplify() ... although it makes me wonder:
>>
>>
>>>         err = drm_plane_create_rotation_property(&plane->base,
>>>                                                  DRM_MODE_ROTATE_0,
>>>                                                  DRM_MODE_ROTATE_0 |
>>> +                                                DRM_MODE_ROTATE_180 |
>>>                                                  DRM_MODE_REFLECT_X |
>>>                                                  DRM_MODE_REFLECT_Y);
>>
>> Would it make sense for drm_plane_create_rotation_property() itself,
>> to add DRM_MODE_ROTATE_180, when both reflections are supported?
> 
> Hello Emil,
> 
> That's a good point! All DRM_MODE_ROTATE_180 should be removed because
> Tegra can't do 180° + reflected-x. The DRM core takes care of 180°
> rotation when both x/y reflections are supported.
> 

I just found out that I forgot to drop the WIP patches which added
transparent rotation support while was checking whether these plane
DRM_MODE_ROTATE_180 could be dropped and it's actually need to be set
for the planes, otherwise 180 rotation support is filtered out by the
atomic check.