From dd2b4a7abf82d88261f8f98e1361388a7db2ffe4 Mon Sep 17 00:00:00 2001 From: "Zhang, Rui" Date: Wed, 24 Feb 2010 09:38:49 +0800 Subject: ALSA: hda - remove unnecessary msleep on power state transitions This will save ~15ms boot time. The first 10ms sleep was introduced in commit d2595d86e5 for (buggy) Cxt codecs, so better to limit the sleep to the problem hardware. For the second 10ms sleep, the HDA spec says: Power State[1:0]: 00: Node Power state (D0) is fully on. 01: Node Power state (D1) allows for (does not require) the lowest possible power consuming state from which it can return to the "fully on" state (D0) within 10 ms, excepting analog pass through circuits (e.g., CD analog playback) which must remain fully on. 10: Node Power state (D2) allows for (does not require) the lowest possible power consuming state from which it can return to the "fully on" state (D0) within 10 ms. For modems, this is the "wake on ring" power state. 11: Node Power state (D3) allows for (does not require) lowest possible power consuming state under software control. Note that any low power state set by software must retain sufficient operational capability to properly respond to subsequent software Power State command. So 10ms is actually the max wait time. It should be safe to remove/reduce it and rely on the loop of 1ms-sleeps. CC: Marc Boucher CC: Arjan van de Ven Signed-off-by: Zhang Rui Signed-off-by: Wu Fengguang Signed-off-by: Takashi Iwai --- sound/pci/hda/hda_codec.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'sound') diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c index 98767df4f03..76d3c4c049d 100644 --- a/sound/pci/hda/hda_codec.c +++ b/sound/pci/hda/hda_codec.c @@ -2767,7 +2767,8 @@ static void hda_set_power_state(struct hda_codec *codec, hda_nid_t fg, snd_hda_codec_read(codec, fg, 0, AC_VERB_SET_POWER_STATE, power_state); /* partial workaround for "azx_get_response timeout" */ - if (power_state == AC_PWRST_D0) + if (power_state == AC_PWRST_D0 && + (codec->vendor_id & 0xffff0000) == 0x14f10000) msleep(10); nid = codec->start_nid; @@ -2801,7 +2802,6 @@ static void hda_set_power_state(struct hda_codec *codec, hda_nid_t fg, if (power_state == AC_PWRST_D0) { unsigned long end_time; int state; - msleep(10); /* wait until the codec reachs to D0 */ end_time = jiffies + msecs_to_jiffies(500); do { -- cgit v1.2.3-70-g09d2