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Commit 5a9a5179 authored by Denis V. Lunev's avatar Denis V. Lunev Committed by Takashi Iwai
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ALSA: intel8x0: Improve comments for VM optimization 



The recently merged 228cf793 looks a bit hackish while it is not.
The change was quite simple. In a virtualized environment the
patch unhacks old kludge introduced for old broken AC97 hardware.

This patch adds proper comment to "unkludge" code.

Signed-off-by: default avatarDenis V. Lunev <den@openvz.org>
Signed-off-by: default avatarKonstantin Ozerkov <kozerkov@parallels.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 1ea6b8f4

sound/pci/intel8x0.c

+7 −0
Original line number Diff line number Diff line
@@ -1077,6 +1077,13 @@ static snd_pcm_uframes_t snd_intel8x0_pcm_pointer(struct snd_pcm_substream *subs 
		}

		if (civ != igetbyte(chip, ichdev->reg_offset + ICH_REG_OFF_CIV))

			continue;



		/* IO read operation is very expensive inside virtual machine

		 * as it is emulated. The probability that subsequent PICB read

		 * will return different result is high enough to loop till

		 * timeout here.

		 * Same CIV is strict enough condition to be sure that PICB

		 * is valid inside VM on emulated card. */

		if (chip->inside_vm)

			break;

		if (ptr1 == igetword(chip, ichdev->reg_offset + ichdev->roff_picb))