Hello Torstein and list;
On Thu, Mar 7, 2013 at 12:30 PM, Torstein Hegge <hegge@xxxxxxxxxxx> wrote:
> On Wed, Mar 06, 2013 at 01:15:06PM -0800, chris hermansen wrote:
>> Does this help?
>
> Kind of, but it doesn't bring me much closer to understanding why this happens.
> It would be nice if I could reproduce this.
>
> This might not be relevant at all, but could you try to do this change on top
> of v3 of the patch, reproduce the the bug and look at /var/log/kern.log?
Ok, so see below for the results.
>
> diff --git a/sound/usb/clock.c b/sound/usb/clock.c
> index 98c4e26..746ec9b 100644
> --- a/sound/usb/clock.c
> +++ b/sound/usb/clock.c
> @@ -304,7 +304,7 @@ static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
>
> cur_rate = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
> if (cur_rate != rate) {
> - snd_printd(KERN_WARNING
> + snd_printk(KERN_WARNING
> "current rate %d is different from the runtime rate %d\n",
> cur_rate, rate);
> }
> @@ -330,8 +330,21 @@ static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
> case USB_ID(0x0d8c, 0x0315): /* CM6632A */
> case USB_ID(0x0d8c, 0x0319): /* CM6631A */
> case USB_ID(0x200c, 0x1030): /* Reloop */
> - usb_set_interface(dev, iface, 0);
> - usb_set_interface(dev, iface, fmt->altsetting);
> + snd_printk(KERN_WARNING
> + "%d:%d: resetting device after change %d -> %d\n",
> + dev->devnum, iface, prev_rate, cur_rate);
> + err = usb_set_interface(dev, iface, 0);
> + if (err < 0) {
> + snd_printk(KERN_WARNING
> + "%d:%d:%d: cannot reset interface (%d)\n",
> + dev->devnum, iface, 0, err);
> + }
> + err = usb_set_interface(dev, iface, fmt->altsetting);
> + if (err < 0) {
> + snd_printk(KERN_WARNING
> + "%d:%d:%d: cannot set interface (%d)\n",
> + dev->devnum, iface, fmt->altsetting, err);
> + }
> break;
> }
> }
Going sideways here for a minute - I'm using apt to get the Ubuntu
kernel source for 3.8.0 as opposed to git, so I'm trying to match your
process with patch.
The v3 patch works fine but applying the above doesn't; I get errors
clh@temuko:~/test$ patch clock.c ../patch.th.debug
patching file clock.c
Hunk #1 FAILED at 304.
Hunk #2 FAILED at 330.
2 out of 2 hunks FAILED -- saving rejects to file clock.c.rej
clh@temuko:~/test$
So I manipulated the file by hand.
The build all seemed to go fine.
>
> There are multiple possible outcomes:
>
> 1) It fixes the issue. In that case the problem must be very timing
> sensitive.
>
> 2) The first printk hits. Then the device lies about the current rate.
>
> 3) The second printk does not hit. Then the device the device lies about the
> previous rate.
>
> 4) The reset operation fails. Unlikely, but I should probably have checked the
> reported error code anyway.
>
> 5) No change. usb_set_interface() after setting sample rate is not always
> enough, the device needs to be kicked even harder.
>
> My guess is 5.
As to the outcome, I have two.
The first is that the problem seems worse now - I get more songs going
into staticky noisy mode.
The second is the attached excerpt of the kernel log file.
Please let me know if you'd like to try something else.
--
Chris Hermansen · clhermansen "at" gmail "dot" com
C'est ma façon de parler.
Attachment:
kern.log.test
Description: Binary data
------------------------------------------------------------------------------ Symantec Endpoint Protection 12 positioned as A LEADER in The Forrester Wave(TM): Endpoint Security, Q1 2013 and "remains a good choice" in the endpoint security space. For insight on selecting the right partner to tackle endpoint security challenges, access the full report. http://p.sf.net/sfu/symantec-dev2dev
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