At Fri, 29 Aug 2008 11:35:25 +0200 (CEST), noreply-git@alsa-project.org wrote:

commit 1328f04260822e45a2717b65a0e2bc0c9c1255be Author: Jaroslav Kysela perex@perex.cz AuthorDate: Fri Aug 29 11:29:39 2008 +0200 Commit: Jaroslav Kysela perex@perex.cz CommitDate: Fri Aug 29 11:29:39 2008 +0200

ALSA: intel8x0: implement ac97_clock whitelist

The AC97 clock detection is not accurate in some cases. This patch adds
an initial whitelist for audio devices gathered from RedHat's bugzilla:

https://bugzilla.redhat.com/show_bug.cgi?id=441087

As a side effect, white-listing might speedup kernel booting (AC97 clock
measuring code is not activated).

Signed-off-by: Jaroslav Kysela <perex@perex.cz>

(snip)

+struct intel8x0_clock_list {

• unsigned short subvendor;
• unsigned short subdevice;
• unsigned int rate;

+};

+static struct intel8x0_clock_list intel8x0_clock_list[] __devinitdata = {

• { 0x1028, 0x00be, 44100 }, /* Analog Devices AD1885 */
• { 0x1028, 0x0177, 48000 }, /* Analog Devices AD1980 */
• { 0x1043, 0x80f3, 48000 }, /* Analog Devices AD1985 */
• { 0x0000, 0x0000, 00000 } /* terminator */

+};

+static int __devinit intel8x0_in_clock_list(struct intel8x0 *chip) +{

• struct pci_dev *pci = chip->pci;
• struct intel8x0_clock_list *wl;
• for (wl = intel8x0_clock_list; wl->subvendor; wl++) {

• if (wl->subvendor == pci->subsystem_vendor &&
  

•     wl->subdevice == pci->subsystem_device) {
  

•     	printk(KERN_INFO "intel8x0: white list rate for %04x:%04x is %i\n",
  

•     		pci->subsystem_vendor,
  

•     		pci->subsystem_device, wl->rate);
  

• 	chip->ac97_bus->clock = wl->rate;
  

• 	return 1;
  

• }
  

• }
• return 0;

+}

Use snd_pci_quirk_lookup() please.

But, a better fix would be to fix the clock measurement. AFAIK, this seems to happen when the driver is built-in. Thus I guess it's rather a problem of time-keeping core side.

Takashi