[MPlayer-dev-eng] [BUG] usage of /dev/rtc causes jerky playback (defies cache?)

[Gabucino]

I've been experiencing jerky playback sometimes for a while now, but failed
to find the reason until just now. Previously I thought it's a kernel
scheduler - O(1) - problem.

My sister was grabbing an audio CD into mp3 using "cdparanoia ... | lame ..."
on my non-DMA DVD drive. I launched MPlayer on a 640x285 divx avi
_from HDD_, just to find it jerky. Then started xine, and I could see the
jerkiness is gone :)

After some experimenting, I found that disabling RTC usage (I moved it away
from /dev :) _AND_ increasing cache from 1024k to 32768k flawlessly solves the
problem. Note that using 32Mb cache AND using RTC _is still_ jerky.

Jerky = both video and audio playback comes to a stop in every for ~0.5
        second. In my case this happens when NONE of HDD or DVD leds are
        blinking, and always then.

A status line just in the moment of halting, 32Mb cache+RTC:
A:  27.4 V:  27.4 A-V: -0.001 ct: -0.001  686/686  63%  0%  3.0% 96 0 86%

After continuation of playing, the A/V sync jumps for a ~0.3 second, then
stabilizes:
A:  43.0 V:  42.8 A-V:  0.194 ct:  0.026  1071/1071  90%  0%  4.6% 212 0 78%

Using framedrop or not: doesn't seem to matter.

Guess it's some hardware bug, but it's very noticable when playing
movie FROM my drive (no DMA), and using RTC. So it shouldn't be uncommon,
and I suggest some workaround, maybe disabling RTC support.

Playing divxes with lower resolution doesn't trigger the problem.

AMD K6/2-500, sb live 5.1 - OSS emu10k1

-- 
Gabucino

May the Playtree be with you!
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