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Re: framebuffer corruption due to overlapping stp instructions on arm64
- From: Mikulas Patocka <mpatocka at redhat dot com>
- To: Ard Biesheuvel <ard dot biesheuvel at linaro dot org>
- Cc: Florian Weimer <fweimer at redhat dot com>, Andrew Pinski <pinskia at gmail dot com>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>, Ramana Radhakrishnan <ramana dot gcc at googlemail dot com>, Thomas Petazzoni <thomas dot petazzoni at free-electrons dot com>, GNU C Library <libc-alpha at sourceware dot org>, Catalin Marinas <catalin dot marinas at arm dot com>, Will Deacon <will dot deacon at arm dot com>, Russell King <linux at armlinux dot org dot uk>, LKML <linux-kernel at vger dot kernel dot org>, linux-arm-kernel <linux-arm-kernel at lists dot infradead dot org>
- Date: Mon, 6 Aug 2018 08:09:50 -0400 (EDT)
- Subject: Re: framebuffer corruption due to overlapping stp instructions on arm64
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On Mon, 6 Aug 2018, Ard Biesheuvel wrote:
> >> Are we talking about a quirk for the Armada 8040 or about PCIe on ARM
> >> in general?
> > I don't know - there are not any other easily available PCIe ARM boards
> > except for Armada 8040.
> ... indeed, and sadly, the ones that are available all have this
> horrible Synopsys DesignWare PCIe IP that does not implement a true
> root complex at all, but is simply repurposed endpoint IP with some
> tweaks so it vaguely resembles a root complex.
> But this is exactly why I am asking: I use a AMD Seattle Overdrive as
> my main Linux development system, and it runs the gnome-shell stack
> flawlessly (using the nouveau driver), as well as a UEFI framebuffer
> using efifb. So my suspicion is that this is either a Synopsys IP
> issue or an interconnect issue, and has nothing to do with the
> impedance mismatch between AMBA and PCIe.
If you run the program for testing memcpy on framebuffer that I posted in
this thread - does it detect some corruption for you?
BTW. does the Radeon GPU driver work for you?
My observation is that OpenGL with Nouveau works, but it's slow and the
whole system locks up when playing video in chromium.
Radeon HD 6350 (pre-GCN), doesn't lock up, but OpenGL (and Glamour) has
many artifacts and corrupted textures. When I switch it to EXA
acceleration and don't use OpenGL, it works.
The artifacts are not fixed by preloading a glibc with fixed memcpy, so
there's supposedly some other bug somewhere.
Unfortunatelly, there's no low-power GCN card.