On Jun 9 2017 15:53, Takashi Iwai wrote:
From: Takashi Iwai <tiwai@xxxxxxx>
Subject: [PATCH] ALSA: pcm: Suppress status/control mmap when ack ops is
present
The drivers using PCM ack ops require the notification whenever
appl_ptr is updated in general. But when the PCM status/control page
is mmapped, this notification doesn't happen, per design, thus it's
not guaranteed to receive the fine-grained updates.
For improving the situation, this patch simply suppresses the PCM
status/control mmap when ack ops is defined. At least, for all
existing drivers with ack, this should give more benefit.
Once when we really need the full optimization with status/control
mmap even using ack ops, we may reconsider the check, e.g. introducing
a new flag. But, so far, this should be good enough.
Yes this makes sense and we tested it for us, looks good
Reveiwed-by: Vinod Koul <vinod.koul@xxxxxxxxx>
Tested-by: Subhransu S. Prusty <subhransu.s.prusty@xxxxxxxxx>
OK, thanks.
If Sakamato-san is happy with this change, I'm going to merge it for
4.13.
I'm writing a long long message about my concern for this patch. I'm
happy if you postpone application to your for-next branch, till next week.
Thanks
Takashi Sakamoto
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