tiomap-dev team mailing list archive

[Ricardo Salveti <rsalveti@xxxxxxxxxxxx>]

SRU Justification:

Impact: While using SGX acceleration on Pandaboard, it's quite normal to face
the GFX_FIFO_UNDERFLOW issue, that disable the display entirely. The only
way to get the screen back to work is to reset it, or by changing to a text mode
session and then getting back to X11. This issue makes practically impossible
to use and stress the SGX driver on a Full HD monitor.

Fix: While TI still didn't provide a proper way to fix is, a valid workaround was
proposed to use the writeback buffers for GFX. The proposed patches are all
already applied at Natty's branch, and this is basically a backport of them for
Maverick.

Testcase: Just run Unity using the SGX driver on a Full HD monitor, and try to
use it normally, and your screen will probably get black with the following
message at your dmesg:
[ 404.169006] omapdss DISPC error: GFX_FIFO_UNDERFLOW, disabling GFX
After applying these patches, you should be able to normally use Unity, without
heading into any underflow issue.

-- 
You received this bug notification because you are a member of TI OMAP
Developers, which is a subscriber of a duplicate bug (655746).
https://bugs.launchpad.net/bugs/653002

Title:
  omapdss DISPC error: GFX_FIFO_UNDERFLOW, disabling GFX

Status in “linux-ti-omap4” package in Ubuntu:
  In Progress

Bug description:
  Platform: Panda board, 8 layers.
Processor: TI OMAP4

Symptom:  The screen will go black randomly - even when there is activity - and doesn't come back.  The following output can be found on the serial console (when enabled) and the log file:

 [  404.169006] omapdss DISPC error: GFX_FIFO_UNDERFLOW, disabling GFX

To recover the screen, change to another console and get back to tty7: CTRL + ALT + F1 followed by CTRL + ALT + F7

This is a known problem that is currently being addressed by TI.