Re: [PATCH] ALSA: hda-intel - Disable MSI support by default

From: Linus Torvalds
Date: Wed Nov 15 2006 - 15:16:36 EST




On Wed, 15 Nov 2006, Mws wrote:
>
> after some small discussions on alsa-user ml i recognised this
> thread today.
> i thought my problem could also exist on this msi stuff.
> i disabled msi in kernel config, reboot, and, after starting x & kde
> i got immediately a freeze.
> last and maybe important last try has been to
> enable msi support _but_ boot kernel with cmdline pci=nomsi
> this finally did work out. i got a working sound environment again.

I expect that you have the exact same issue as Olivier: the "hang" is
probably because you started using the sound device (beeping on the
console is handled by the old built-in speaker, but in X a single beep
tends to be due to sound device drivers), and because of sound irq
misrouting you had some other device (like your harddisk) that got their
irq disabled due to the "nobody cared" issue.

> i find it a bit abnormal that the disabling msi in kernel config behaviour
> is different from kernel cmdline pci=nomsi option.

Now, that does actually worry me. It _should_ have worked with CONFIG_MSI
disabled. I wonder if some of the MSI workarounds actually broke the HDA
driver subtly.

Anyway, it would be a good idea to test the current -git tree if you can,
both with CONFIG_MSI and without (and _without_ any "pci=nomsi" kernel
command line). It should hopefully work, exactly because the HDA driver
now shouldn't even try to do any MSI stuff by default.

Knock wood.

Linus
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