On 09/05/14 17:37, Tony Lindgren wrote:

* Tomi Valkeinen [off-list ref] [140509 00:39]:

quoted

On 30/04/14 02:52, Tony Lindgren wrote:

quoted

Otherwise we can get often errors like the following and the
display won't come on:

omapdss APPLY error: FIFO UNDERFLOW on gfx, disabling the overlay
omapdss APPLY error: SYNC_LOST on channel lcd, restarting
the output with video overlays disabled

There are some earlier references to this issue:

http://www.spinics.net/lists/linux-omap/msg59511.html
http://www.spinics.net/lists/linux-omap/msg59724.html

Those don't sound like the same issue, but it's hard to say. What kind
of clock rates do you get? Cat you paste debugfs/omapdss/clk, with and
without this patch?

Without this patch:
# cat /sys/kernel/debug/omapdss/clk 
[   24.833831] DSS: dss_runtime_get
[   24.837554] DSS: dss_runtime_put
[   24.840972] DISPC: dispc_runtime_get
[   24.844757] DISPC: dispc_runtime_put
- DSS -
DSS_FCK (DSS1_ALWON_FCLK) = 57600000
- DISPC -
dispc fclk source = DSS_FCK (DSS1_ALWON_FCLK)
fck             57600000        
- LCD -
LCD clk source = DSS_FCK (DSS1_ALWON_FCLK)
lck             57600000        lck div 1
pck             19200000        pck div 3


With this patch:
# cat /sys/kernel/debug/omapdss/clk 
[   34.580688] DSS: dss_runtime_get
[   34.584197] DSS: dss_runtime_put
[   34.587768] DISPC: dispc_runtime_get
[   34.591552] DISPC: dispc_runtime_put
- DSS -
DSS_FCK (DSS1_ALWON_FCLK) = 108000000
- DISPC -
dispc fclk source = DSS_FCK (DSS1_ALWON_FCLK)
fck             108000000       
- LCD -
LCD clk source = DSS_FCK (DSS1_ALWON_FCLK)
lck             108000000       lck div 1
pck             18000000        pck div 6
 

quoted

What resolution do you have? If it's a very high resolution (say, DVI
output to a monitor), it could just be an issue of
not-enough-memory-bandwidth.

This is just the 3730-evm with the Sharp VGA panel mentioned in
this series.

Hmm, well, those both look fine. The fck is well below the maximum,
which is somewhere around 170MHz-180MHz. The lck/pck ratio is higher
with this patch, but that should affect the GFX overlay.

So you're just booting, and there are no applications that use the
framebuffer? And there is no rotation or such configured?

 Tomi


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