On 26/03/12 05:59 AM, Alex Deucher wrote:
On Sun, Mar 25, 2012 at 5:39 PM, Connor Behan<[email protected]> wrote:
I really hope some one here is knowledgeable about this...
My r128 card hangs indefinitely if any kind of acceleration is enabled.
Running startx results in a black screen and I have to reboot with
Alt+SysRq+REISUB. This was not caused by upgrading between any official
releases of linux, xorg or my driver. It was caused because I was trying to
hack my driver and I can tell you exactly how.
I was working on adding EXA support to xf86-video-r128. I successfully got
as far as https://bugs.freedesktop.org/show_bug.cgi?id=47866 and I still
suggest that you accept this patch since it does not contain the dangerous
part. The dangerous part came when I tried to support compositing as this
needed some OUT_RING and OUTREG commands. I based this on the KAA approach:
http://cgit.freedesktop.org/xorg/xserver/tree/hw/kdrive/ati?id=0cd662ea80579c317d706ebe04971bb29d0f9b4f
r128_composite.c. When I was finished, I ended up with an r128_exa.c file
that looked like this: http://pastebin.com/HHsESs9q. Now I realize that I
may be asking a difficult question as many of you haven't worked on this
stuff for years, but here's how it went.
I installed this new DDX and first tried to start the X server with EXA and
DRI but the composite extension turned off. Just to make sure that
everything that worked before still worked. However, it did not work. It
gave me this log file: http://pastebin.com/XWYbtTcL showing the lines:
R128(0): R128CCEWaitForIdle: (DEBUG) CCE idle took i = 1025 and R128(0):
Idle timed out, resetting engine...
I then stupidly thought "okay, maybe the composite code that has been added
hangs if composite is disabled so I'll enable composite as well as EXA and
DRI" Doing that gave me the log file: http://pastebin.com/3RJBNhAx with the
lines: (**) R128(0): Idle timed out: 64 entries, stat=0x80400040,
probe=0x00200000, (EE) R128(0): Idle timed out, resetting engine..., (EE)
R128(0): R128WaitForIdle: CCE stop -22, (EE) R128(0): R128WaitForIdle: CCE
reset -22 and (EE) R128(0): R128WaitForIdle: CCE start -22
I get the same error if I switch back to XAA with DRI on. If I use XAA with
DRI off, I get the log file: http://pastebin.com/VLEbsAfx with the line:
(EE) R128(0): Idle timed out, resetting engine... As of this morning, the
ONLY way for me to use X, regardless of what my package versions are is to
specify "NoAccel" which is slow as hell. I've seen R128 infinite loop idling
errors posted to mailing lists in the past. They are mostly posted by PPC
users for whom the r128 driver never worked properly in the first place.
They all say that they "fix" it by turning off acceleration. I obviously
don't want this since my card worked perfectly with 2D and 3D acceleration
for years and it's only my foolishness right now that broke it.
Does anyone know a way this can be fixed? Does ATI provide a tool that will
reflash a VBIOS and get rid of this error? Or does one of you have / know
how to write this kind of utility? Is it common to permanently brick a GPU
if you try writing the wrong bit to a register? Like the ones that are
written to in my r128_exa.c? If so I have even more respect for open source
driver hackers.
There's not really an easy way to wreck your vbios from bad
acceleration code. Moreover, all the vbios handles is modesetting and
card posting. The vbios does not load the cce ucode or touch anything
acceleration related. If you get something on the screen at boot,
then most likely your vbios is fine. I would guess that your system
is not using the ddx (xf86-video-r128) you think it is or your patches
made some subtle change that broke XAA. Does reverting the stock
versions of the graphics stack provided by your distro help?
Alex
At the time, reverting to default versions didn't help. But the problem
has been resolved. I had to unplug my computer for a few hours. I guess
there was corrupted memory that needed time to fade away. So, no need to
read all the pastes that I posted... yet.
The idiocy that caused this was shifting the DATATYPEs 16 bits to the
left. This was explicitly done in the KAA code but the new r128_reg.h
already accounts for this shift in the definitions of the DATATYPEs. So
I now got the KAA code to work but I'm beginning to think it never
worked very well. I will try making it less restrictive about what
pixman formats it allows and report back with my findings.
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