From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755698Ab1KVIAm (ORCPT ); Tue, 22 Nov 2011 03:00:42 -0500 Received: from mga09.intel.com ([134.134.136.24]:12618 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755384Ab1KVIAl (ORCPT ); Tue, 22 Nov 2011 03:00:41 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,352,1309762800"; d="scan'208";a="78681879" Date: Tue, 22 Nov 2011 16:00:38 +0800 From: Wu Fengguang To: Takashi Iwai Cc: "alsa-devel@alsa-project.org" , LKML Subject: Re: [PATCH 2/3] hda - delayed ELD repoll Message-ID: <20111122080038.GA22354@localhost> References: <20111116082945.414733231@intel.com> <20111116083514.568265053@intel.com> <20111121064811.GA24027@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 22, 2011 at 03:30:24PM +0800, Takashi Iwai wrote: > At Mon, 21 Nov 2011 14:48:11 +0800, > Wu Fengguang wrote: > > > > On Wed, Nov 16, 2011 at 04:29:47PM +0800, Wu, Fengguang wrote: > > > The Intel HDMI chips (ironlake at least) are found to have ~250ms delay > > > between the ELD_Valid=1 hotplug event is send and the ELD buffer becomes > > > actually readable. During the time the ELD buffer is mysteriously all 0. > > > > > > Fix it by scheduling a delayed work to re-read ELD buffer after 300ms. > > > > Just FYI. > > > > Up to now the 300ms looks sufficient. But if ever there comes longer > > delays, I've already prepared a patch for retrying it for several times ;) > > Thanks. I think it's safer to have a repoll mechanism. > But, looking at the patch, one question remains: > > > @@ -989,10 +990,9 @@ static void hdmi_present_sense(struct hd > > if (eld_valid) { > > if (!snd_hdmi_get_eld(eld, codec, pin_nid)) > > snd_hdmi_show_eld(eld); > > - else if (retry) { > > + else if (repoll) { > > queue_delayed_work(codec->bus->workq, > > - &per_pin->work, > > - msecs_to_jiffies(300)); > > + &per_pin->work, repoll * HZ / 3); > > Do you really want to wait longer with a higher repoll number? I think it would be good to keep constant repoll intervals (it's cheap after all), but at the same time lift the retry time from 3 to 6. I did this patch when I got the graphics driver side wrong and triggered the hotplug event rather early. At the time I find that it failed until the 3rd repoll (300ms + 600ms + 900ms). Thanks, Fengguang --- Subject: hda - repoll ELD content for multiple times Date: Fri Nov 18 16:59:32 CST 2011 Improve the one-shot ELD repoll to up to 6 retries. Up to now the 300ms looks sufficient for the test boxes. However I'm a bit worried about how well it can fit the wider user base. Signed-off-by: Wu Fengguang --- sound/pci/hda/patch_hdmi.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) --- linux.orig/sound/pci/hda/patch_hdmi.c 2011-11-22 15:50:21.000000000 +0800 +++ linux/sound/pci/hda/patch_hdmi.c 2011-11-22 15:50:41.000000000 +0800 @@ -69,6 +69,7 @@ struct hdmi_spec_per_pin { struct hda_codec *codec; struct hdmi_eld sink_eld; struct delayed_work work; + int repoll_count; }; struct hdmi_spec { @@ -748,7 +749,7 @@ static void hdmi_setup_audio_infoframe(s * Unsolicited events */ -static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, bool retry); +static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll); static void hdmi_intrinsic_event(struct hda_codec *codec, unsigned int res) { @@ -766,7 +767,7 @@ static void hdmi_intrinsic_event(struct if (pin_idx < 0) return; - hdmi_present_sense(&spec->pins[pin_idx], true); + hdmi_present_sense(&spec->pins[pin_idx], 1); } static void hdmi_non_intrinsic_event(struct hda_codec *codec, unsigned int res) @@ -960,7 +961,7 @@ static int hdmi_read_pin_conn(struct hda return 0; } -static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, bool retry) +static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll) { struct hda_codec *codec = per_pin->codec; struct hdmi_eld *eld = &per_pin->sink_eld; @@ -989,7 +990,7 @@ static void hdmi_present_sense(struct hd if (eld_valid) { if (!snd_hdmi_get_eld(eld, codec, pin_nid)) snd_hdmi_show_eld(eld); - else if (retry) { + else if (repoll) { queue_delayed_work(codec->bus->workq, &per_pin->work, msecs_to_jiffies(300)); @@ -1004,7 +1005,10 @@ static void hdmi_repoll_eld(struct work_ struct hdmi_spec_per_pin *per_pin = container_of(to_delayed_work(work), struct hdmi_spec_per_pin, work); - hdmi_present_sense(per_pin, false); + if (per_pin->repoll_count++ > 6) + per_pin->repoll_count = 0; + + hdmi_present_sense(per_pin, per_pin->repoll_count); } static int hdmi_add_pin(struct hda_codec *codec, hda_nid_t pin_nid) @@ -1235,7 +1239,7 @@ static int generic_hdmi_build_jack(struc if (err < 0) return err; - hdmi_present_sense(per_pin, false); + hdmi_present_sense(per_pin, 0); return 0; }