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From: "Michel Dänzer" <michel@daenzer.net>
To: Gerd Hoffmann <kraxel@redhat.com>,
	David Airlie <airlied@linux.ie>, Sean Paul <sean@poorly.run>
Cc: dri-devel@lists.freedesktop.org,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/5] drm: fix drm_mode_addfb() on big endian machines.
Date: Mon, 3 Sep 2018 19:01:55 +0200	[thread overview]
Message-ID: <cf3310b2-dad4-63a3-f420-417d430f0a98@daenzer.net> (raw)
In-Reply-To: <20180903164558.GL21634@phenom.ffwll.local>

On 2018-09-03 6:45 p.m., Daniel Vetter wrote:
> On Mon, Sep 03, 2018 at 12:57:54PM +0200, Gerd Hoffmann wrote:
>> Userspace on big endian machhines typically expects the ADDFB ioctl
>> returns a big endian framebuffer.  drm_mode_addfb() will call
>> drm_mode_addfb2() unconditionally with little endian DRM_FORMAT_*
>> values though, which is wrong.  This patch fixes that.
>>
>> Drivers (both kernel and xorg) have quirks in place to deal with the
>> broken drm_mode_addfb() behavior.  Because of this we can't just change
>> drm_mode_addfb() behavior for everybody without breaking things.  So add
>> a new driver feature flag DRIVER_PREFER_HOST_BYTE_ORDER, so drivers can
>> opt-in.

Since the changes are opt-in now, they shouldn't affect drivers which
don't opt in; they should work as well (or as badly :) after these
changes as they did before. So no concerns from my side anymore.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer

WARNING: multiple messages have this Message-ID (diff)
From: "Michel Dänzer" <michel@daenzer.net>
To: Gerd Hoffmann <kraxel@redhat.com>,
	David Airlie <airlied@linux.ie>, Sean Paul <sean@poorly.run>
Cc: open list <linux-kernel@vger.kernel.org>,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 3/5] drm: fix drm_mode_addfb() on big endian machines.
Date: Mon, 3 Sep 2018 19:01:55 +0200	[thread overview]
Message-ID: <cf3310b2-dad4-63a3-f420-417d430f0a98@daenzer.net> (raw)
In-Reply-To: <20180903164558.GL21634@phenom.ffwll.local>

On 2018-09-03 6:45 p.m., Daniel Vetter wrote:
> On Mon, Sep 03, 2018 at 12:57:54PM +0200, Gerd Hoffmann wrote:
>> Userspace on big endian machhines typically expects the ADDFB ioctl
>> returns a big endian framebuffer.  drm_mode_addfb() will call
>> drm_mode_addfb2() unconditionally with little endian DRM_FORMAT_*
>> values though, which is wrong.  This patch fixes that.
>>
>> Drivers (both kernel and xorg) have quirks in place to deal with the
>> broken drm_mode_addfb() behavior.  Because of this we can't just change
>> drm_mode_addfb() behavior for everybody without breaking things.  So add
>> a new driver feature flag DRIVER_PREFER_HOST_BYTE_ORDER, so drivers can
>> opt-in.

Since the changes are opt-in now, they shouldn't affect drivers which
don't opt in; they should work as well (or as badly :) after these
changes as they did before. So no concerns from my side anymore.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer
_______________________________________________
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  reply	other threads:[~2018-09-03 17:02 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-03 10:57 [PATCH 0/5] drm: byteorder fixes Gerd Hoffmann
2018-09-03 10:57 ` [PATCH 1/5] drm: byteorder: add DRM_FORMAT_HOST_* Gerd Hoffmann
2018-09-03 10:57   ` Gerd Hoffmann
2018-09-03 10:57 ` [PATCH 2/5] drm: do not mask out DRM_FORMAT_BIG_ENDIAN Gerd Hoffmann
2018-09-03 10:57   ` Gerd Hoffmann
2018-09-03 10:57 ` [PATCH 3/5] drm: fix drm_mode_addfb() on big endian machines Gerd Hoffmann
2018-09-03 10:57   ` Gerd Hoffmann
2018-09-03 16:45   ` Daniel Vetter
2018-09-03 17:01     ` Michel Dänzer [this message]
2018-09-03 17:01       ` Michel Dänzer
2018-09-03 17:07     ` Ilia Mirkin
2018-09-04  8:00       ` Michel Dänzer
2018-09-04  8:00         ` Michel Dänzer
2018-09-04 13:05         ` Ilia Mirkin
2018-09-04 13:05           ` Ilia Mirkin
2018-09-04 15:02           ` Michel Dänzer
2018-09-04 15:02             ` Michel Dänzer
2018-09-04 15:15             ` Ilia Mirkin
2018-09-04 15:15               ` Ilia Mirkin
2018-09-05  6:10               ` Gerd Hoffmann
2018-09-03 10:57 ` [PATCH 4/5] drm/bochs: fix DRM_FORMAT_* handling for " Gerd Hoffmann
2018-09-03 10:57   ` Gerd Hoffmann
2018-09-03 10:57 ` [PATCH 5/5] drm/virtio: fix DRM_FORMAT_* handling Gerd Hoffmann
2018-09-03 10:57   ` Gerd Hoffmann
2018-09-03 10:57 ` Gerd Hoffmann

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