linux-kernel - Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues

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Message-ID: <20190110184446.75b4350a@bbrezillon>
Date:   Thu, 10 Jan 2019 18:45:01 +0100
From:   Boris Brezillon <bbrezillon@...nel.org>
To:     Peter Rosin <peda@...ntia.se>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        David Airlie <airlied@...ux.ie>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        Boris Brezillon <boris.brezillon@...tlin.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>
Subject: Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues

On Thu, 10 Jan 2019 15:10:28 +0000
Peter Rosin <peda@...ntia.se> wrote:

> Hi!
> 
> I found an unfortunate issue while recoding plane handling to use
> drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
> which is not correct. I simply fixed it (patch 1/4), but maybe that
> will cause regressions for unsuspecting users who simply assumed
> that the clockwise rotation was correct? I don't know what to do
> about that? Adding an option to get the old broken behavior seems
> useless, wouldn't it be just as easy to just fix whatever app to
> rotate the other way instead of adding an option somewhere?

Hm, rotation support has been added before the standard rotation
property was created, and at that time I assumed rotation was clockwise
(which apparently was an unwise choice). Anyway, I don't have a
solution for this problem, so I'll let Nicolas decide if it's
acceptable to change the rotation behavior.

> 
> I have only tested this series on sama5d3, but I did check the docs
> for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35
> and sam9x35) supported by the driver (relevant to patch 4/4).

Thanks for addressing those problems.

> 
> Cheers,
> Peter
> 
> Peter Rosin (4):
>   drm/atmel-hlcdc: rotate planes counterclockwise
>   drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
>   drm/atmel-hlcdc: fix clipping of planes
>   drm/atmel-hlcdc: do not immediately disable planes, wait for next
>     frame
> 
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 179 +++++++++---------------
>  1 file changed, 67 insertions(+), 112 deletions(-)
>