From mboxrd@z Thu Jan 1 00:00:00 1970 From: bugzilla-daemon@freedesktop.org Subject: [Bug 81476] three monitors on two radeon cards works with some layouts not others Date: Tue, 22 Jul 2014 00:04:16 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============2028016334==" Return-path: Received: from culpepper.freedesktop.org (unknown [131.252.210.165]) by gabe.freedesktop.org (Postfix) with ESMTP id 6237C6E0A3 for ; Mon, 21 Jul 2014 17:04:18 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============2028016334== Content-Type: multipart/alternative; boundary="1405987455.745B6Da1.16769"; charset="us-ascii" --1405987455.745B6Da1.16769 Date: Tue, 22 Jul 2014 00:04:15 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" https://bugs.freedesktop.org/show_bug.cgi?id=81476 --- Comment #20 from Alex Deucher --- (In reply to comment #19) > > I'd believe it as a hardware limitation if inverting the first two monitors > didn't fix it. If I were willing to physically turn my first two monitors > upside-down, it would work fine with the given hardware. The hardware can > display across my three monitors at 4800x1200 as long as two of the screens > are inverted. We just need to make the software put those screens into the > hardware the other way up! As I said before, it only works with rotation because it's scanning out of different buffers when rotation is enabled. When you enable rotation a shadow buffer is created which is a rotated duplicate of the sub-region of the entire desktop. So for the rotated case, the display hw is scanning out of a 1600x1200 surface rather than the full 4800x1200 surface. If you wanted to you could do something similar for the non-rotated case in the xserver, but that would incur an extra copy for every update of the desktop in the non-rotated case. If you want to test further, try and disable acceleration (Option "NoAccel" "true" in the device section of your xorg.conf) or use the modesetting driver (xf86-video-modesetting). You won't be able to use rotation since that requires acceleration do to the rotated blit, but that will take all non-display hw factors (3D, etc.) out of the equation. -- You are receiving this mail because: You are the assignee for the bug. --1405987455.745B6Da1.16769 Date: Tue, 22 Jul 2014 00:04:15 +0000 MIME-Version: 1.0 Content-Type: text/html; charset="UTF-8"

Comment # 20 on bug 81476 from 
(In reply to comment #19)
> 
> I'd believe it as a hardware limitation if inverting the first two monitors
> didn't fix it.  If I were willing to physically turn my first two monitors
> upside-down, it would work fine with the given hardware.  The hardware can
> display across my three monitors at 4800x1200 as long as two of the screens
> are inverted.  We just need to make the software put those screens into the
> hardware the other way up!

As I said before, it only works with rotation because it's scanning out of
different buffers when rotation is enabled.  When you enable rotation a shadow
buffer is created which is a rotated duplicate of the sub-region of the entire
desktop.  So for the rotated case, the display hw is scanning out of a
1600x1200 surface rather than the full 4800x1200 surface.  If you wanted to you
could do something similar for the non-rotated case in the xserver, but that
would incur an extra copy for every update of the desktop in the non-rotated
case.

If you want to test further, try and disable acceleration (Option "NoAccel"
"true" in the device section of your xorg.conf) or use the modesetting driver
(xf86-video-modesetting).  You won't be able to use rotation since that
requires acceleration do to the rotated blit, but that will take all
non-display hw factors (3D, etc.) out of the equation.

You are receiving this mail because:
  • You are the assignee for the bug.
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