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 fengguang.wu@intel.com --- 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; }