From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 20 Aug 2009 14:40:16 +0000 (+0200)
Subject: ALSA: pcm - Fix drain behavior in non-blocking mode
X-Git-Tag: v2.6.32-rc1~732^2~6^2~1
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4cdc115fd38b54642e8536a5c2389483bcb9b2e9;p=pandora-kernel.git

ALSA: pcm - Fix drain behavior in non-blocking mode

The current PCM core has the following problems regarding PCM draining
in non-blocking mode:

- the current f_flags isn't checked in snd_pcm_drain(), thus changing
  the mode dynamically via snd_pcm_nonblock() after open doesn't work.
- calling drain in non-blocking mode just return -EAGAIN error, but
  doesn't provide any way to sync with draining.

This patch fixes these issues.
- check file->f_flags in snd_pcm_drain() properly
- when O_NONBLOCK is set, PCM core sets the stream(s) to DRAIN state
  but quits ioctl immediately without waiting the whole drain; the
  caller can sync the drain manually via poll()

Signed-off-by: Takashi Iwai <tiwai@suse.de>
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