linux-kernel - Re: [PATCH 2/3] hda

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 22 Nov 2011 08:30:24 +0100
From:	Takashi Iwai <tiwai@...e.de>
To:	Wu Fengguang <fengguang.wu@...el.com>
Cc:	"alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/3] hda - delayed ELD repoll

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?


Takashi
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/