On Sun, Apr 26, 2009 at 7:14 AM, Takashi Iwai <tiwai@xxxxxxx> wrote: > At Sat, 25 Apr 2009 17:28:55 -0400, > Jon Smirl wrote: >> >> These new patches have broken audio support on the mpc5200.... > > Then the lowlevel callbacks are likely wrong :) > >> They assume that the hardware is capable of telling where the DMA >> engine is in the middle of an operation. > > Well, nothing new by these patches. The original PCM core > implementation has been designed in that way. These changes may check > some bogus value more strictly. > > If the hardware doesn't support it, it needs report at least some > "sane" value; i.e. it must not be over the real position, but not > below the previous pointer. > In the worst case, the driver just needs to report the same position > at the previous period boundary until the next > snd_pcm_period_elapsed(). That's doesn't work anymore. The PCM code is using jiffies to estimate where the pointer needs to be. I used the same jiffies to fake up a hardware position. > > > Takashi > >> I'm still checking to see if >> I can get that data out of the Bestcomm DMA engine. >> >> jonsmirl@terra:/home/linus/sound/core$ git log pcm_lib.c >> commit bbf6ad1399e9516b0a95de3ad58ffbaed670e4cc >> Author: Jaroslav Kysela <perex@xxxxxxxx> >> Date: Fri Apr 10 12:28:58 2009 +0200 >> >> [ALSA] pcm-midlevel: Add more strict buffer position checks based on jiffies >> >> Some drivers like Intel8x0 or Intel HDA are broken for some >> hardware variants. >> This patch adds more strict buffer position checks based on jiffies when >> internal hw_ptr is updated. Enable xrun_debug to see mangling of wrong >> positions. >> >> As a side effect, the hw_ptr interrupt update routine might do >> slightly better >> job when many interrupts are lost. >> >> Signed-off-by: Jaroslav Kysela <perex@xxxxxxxx> >> >> commit 8b22d943c34b616eefbd6d2f8f197a53b1f29fd0 >> Author: Takashi Iwai <tiwai@xxxxxxx> >> Date: Fri Mar 20 16:26:15 2009 +0100 >> >> ALSA: pcm - Safer boundary checks >> >> Make the boundary checks a bit safer. >> These caese are rare or theoretically won't happen, but nothing >> bad to keep the checks safer... >> >> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> >> >> commit ded652f7024bc2d7b6118b561a44187af30841b0 >> Author: Takashi Iwai <tiwai@xxxxxxx> >> Date: Thu Mar 19 10:08:49 2009 +0100 >> >> ALSA: pcm - Fix delta calculation at boundary overlap >> >> When the hw_ptr_interrupt reaches the boundary, it must check whether >> the hw_base was already lapped and corret the delta value appropriately. >> >> Also, rebasing the hw_ptr needs a correction because buffer_size isn't >> always aligned to period_size. >> >> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> >> >> commit 5f513e1197f27e9a0bcfec0feaac59f976f4a37e >> Author: Takashi Iwai <tiwai@xxxxxxx> >> Date: Thu Mar 19 10:01:47 2009 +0100 >> >> ALSA: pcm - Reset invalid position even without debug option >> >> Always reset the invalind hw_ptr position returned by the pointer >> callback. The behavior should be consitent independently from the >> debug option. >> >> Also, add the printk_ratelimit() check to avoid flooding debug >> prints. >> >> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> >> >> >> >> -- >> Jon Smirl >> jonsmirl@xxxxxxxxx >> _______________________________________________ >> Alsa-devel mailing list >> Alsa-devel@xxxxxxxxxxxxxxxx >> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel >> > -- Jon Smirl jonsmirl@xxxxxxxxx _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
