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. _______________________________________________ Mailing list: https://launchpad.net/~tiomap-dev Post to : [email protected] Unsubscribe : https://launchpad.net/~tiomap-dev More help : https://help.launchpad.net/ListHelp
