tree 12584be660620a36d7161f2c951bea81a3122f5f
parent 4f3a8bc7ba6e34403f36e600bc6f54cf0e0041e4
author Ben Widawsky <ben@bwidawsk.net> 1362445229 -0800
committer Daniel Vetter <daniel.vetter@ffwll.ch> 1362472702 +0100

drm/i915: Capture current context on error

On error, this represents the state of the currently running context at
the time it was loaded.

Unfortunately, since we're hung and can't switch out the context this
may not tell us too much about the most current state of the context,
but does give clues about what has happened since loading.

Thanks to recent doc updates, we have a little more confidence regarding
what is actually in this memory, and perhaps it will help us gain more
insight into certain bugs. AFAICT, the most interesting info is in the
first page. To save space, we only capture the first page. In the
future, we might want to dump more.

Sample of the relevant part of error state:
render ring --- HW Context = 0x01b20000
[0000] 00000000 1100105f 00002028 ffff0880
[0010] 0000209c feff4040 000020c0 efdf0080
[0020] 00002178 00000001 0000217c 00145855
[0030] 00002310 00000000 00002314 00000000

v2: Move error collection to the ring error code
Change format of dump to not confuse intel_error_decode (Chris)
Put the context error object with the others (Chris)
Don't search bound_list instead of active_list (chris)

v3: extract and flatten context recording (daniel)
checkpatch related fixes for the copypasta in debugfs

v4: bug in v3 (Daniel)
-       if ((ring->id == RCS) && error->ccid)
+       if ((ring->id != RCS) || !error->ccid)

References: https://bugs.freedesktop.org/show_bug.cgi?id=55845
Reviewed-by (v2): Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Bikeshed away the redudant parenthese around ring->id != RCS]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>