[Maverick][ti-omap4][SRU][pull-request] Reduce GFX_FIFO_UNDERFLOW issue while using SGX

[Tim Gardner]

On 12/23/2010 10:45 AM, Ricardo Salveti wrote:
> On Thu, Dec 23, 2010 at 2:42 PM, Tim Gardner<tim.gardner at canonical.com>  wrote:
>> On 12/22/2010 09:06 PM, Ricardo Salveti wrote:
>>>
>>> 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.
>>>
>>> BugLink: https://bugs.launchpad.net/bugs/653002
>>>
>>> The following changes since commit
>>> 6aba79f8f85b937596373cda8e266b823395996e:
>>>
>>>    Ubuntu-2.6.35-903.19 (2010-11-16 18:32:27 -0700)
>>>
>>> are available in the git repository at:
>>>    git://kernel.ubuntu.com/rsalveti/ubuntu-maverick.git
>>> omap4-reduce-underflow-issue
>>>
>>> Archit Taneja (2):
>>>        OMAP: DSS2: Fix FIFO Threshold calculations for dispc pipelines
>>>        OMAP: DSS2: Use Writeback buffers for GFX as a temporary fix
>>>
>>> Pavel Nedev (1):
>>>        OMAP: DSS2: Fix array size which stores dispc fifo sizes
>>>
>>>   arch/arm/plat-omap/include/plat/display.h |    2 +-
>>>   drivers/video/omap2/dss/dispc.c           |   29 +++++++++++-
>>>   drivers/video/omap2/dss/display.c         |   25 ++++++----
>>>   drivers/video/omap2/dss/dsi.c             |   20 ++++++--
>>>   drivers/video/omap2/dss/dss.h             |    1 +
>>>   drivers/video/omap2/dss/wb.c              |   70
>>> +++++++++++++++++++++++++++-
>>>   6 files changed, 127 insertions(+), 20 deletions(-)
>>>
>>
>> Fetch my tree from 'git://kernel.ubuntu.com/rtg/ubuntu-maverick.git
>> ti-omap4' to verify that I've applied your patches correctly. You should
>> see:
>>
>>   CC      drivers/video/omap2/dss/wb.o
>> drivers/video/omap2/dss/wb.c: In function 'wb_buffer_state_store':
>> drivers/video/omap2/dss/wb.c:49: error: implicit declaration of function
>> 'dss_get_mainclk_state'
>
> Ouch, sorry about that.
>
> The original patch that I tested on maverick had this change that I
> forgot to apply while making the backport from the patch from Natty's
> branch.
>
> Can you please try it again from the same branch? I forced the update
> with the fixed patch and also built here without any issue.
>
> Thanks!

pulled, applied, and uploaded

-- 
Tim Gardner tim.gardner at canonical.com