Re: [Alsa-devel] [RFC: 2.6.19 patch] snd-hda-intel: default MSI to off

From: Takashi Iwai
Date: Wed Oct 18 2006 - 13:22:16 EST


At Wed, 18 Oct 2006 19:12:50 +0200,
I wrote:
>
> At Wed, 18 Oct 2006 10:02:19 -0700,
> Stephen Hemminger wrote:
> >
> > On Wed, 18 Oct 2006 12:24:54 +0200
> > Takashi Iwai <tiwai@xxxxxxx> wrote:
> >
> > > At Tue, 17 Oct 2006 14:40:53 -0700,
> > > Stephen Hemminger wrote:
> > > >
> > > > On Tue, 17 Oct 2006 23:13:01 +0200
> > > > Adrian Bunk <bunk@xxxxxxxxx> wrote:
> > > >
> > > > > On Thu, Oct 05, 2006 at 11:08:57PM +0200, Prakash Punnoor wrote:
> > > > > > Am Donnerstag 05 Oktober 2006 19:30 schrieb Fatih A????c??:
> > > > > > > 2006/10/5, Prakash Punnoor <prakash@xxxxxxxxxx>:
> > > > > > > > Hi,
> > > > > > > >
> > > > > > > > subjects say it all. Without irqpoll my nic doesn't work anymore. I added
> > > > > > > > Ingo
> > > > > > > > to cc, as my IRQs look different, so it may be a prob of APIC routing or
> > > > > > > > the
> > > > > > > > like.
> > > > > >
> > > > > > > > Can you try booting with pci=nomsi ? I have a similar problem with my
> > > > > >
> > > > > > I used snd-hda-intel.disable_msi=1 and this actually helped! Now the nforce
> > > > > > nic works w/o problems. So it was the audio driver causing havoc on the nic.
> > > > > >...
> > > > >
> > > > > Unless someone finds and fixes what causes such problems, I'd therefore
> > > > > suggest the patch below to let MSI support to be turned off by default.
> > > > >
> > > > > cu
> > > > > Adrian
> > > > >
> > > >
> > > > It shouldn't be that hard to write a small bit of code to force an interrupt
> > > > and catch it, that's what other drivers do to workaround the BIOS braindamage
> > > > that seems to be rampant (until M$ Vista comes out and supports MSI).
> > >
> > > OK, what about a patch like below?
> > >
> > > It's against the latest ALSA tree, so please pull alsa.git from
> > > git://kernel.org/pub/scm/linux/kernel/git/perex/alsa.git
> > > before applying it (this tree includes only patches to be pushed to
> > > 2.6.19).
> > >
> > >
> > > Takashi
> > >
> >
> > Don't you need to check return value from pci_enable_msi()?
>
> Yes, it would be better to check the value and reset chip->msi if
> not successful. But it's not a fatal error, so the current code
> should work.

The below is the revised patch.


Takashi

diff -r 74a0618b5f3e sound/pci/hda/hda_intel.c
--- a/sound/pci/hda/hda_intel.c Wed Oct 18 19:09:46 2006 +0200
+++ b/sound/pci/hda/hda_intel.c Wed Oct 18 19:17:48 2006 +0200
@@ -337,6 +337,7 @@ struct azx {
unsigned int initialized :1;
unsigned int single_cmd :1;
unsigned int polling_mode :1;
+ unsigned int msi :1;
};

/* driver types */
@@ -397,6 +398,7 @@ static char *driver_short_names[] __devi
*/
#define upper_32bit(addr) (sizeof(addr) > 4 ? (u32)((addr) >> 32) : (u32)0)

+static int azx_acquire_irq(struct azx *chip, int do_disconnect);

/*
* Interface for HD codec
@@ -535,6 +537,18 @@ static unsigned int azx_rirb_get_respons
return chip->rirb.res; /* the last value */
schedule_timeout_interruptible(1);
} while (time_after_eq(timeout, jiffies));
+
+ if (chip->msi) {
+ snd_printk(KERN_WARNING "hda_intel: No response from codec, "
+ "disabling MSI...\n");
+ free_irq(chip->irq, chip);
+ chip->irq = -1;
+ pci_disable_msi(chip->pci);
+ chip->msi = 0;
+ if (azx_acquire_irq(chip, 1) < 0)
+ return -1;
+ goto again;
+ }

if (!chip->polling_mode) {
snd_printk(KERN_WARNING "hda_intel: azx_get_response timeout, "
@@ -1364,6 +1378,20 @@ static int __devinit azx_init_stream(str
return 0;
}

+static int azx_acquire_irq(struct azx *chip, int do_disconnect)
+{
+ if (request_irq(chip->pci->irq, azx_interrupt, IRQF_DISABLED|IRQF_SHARED,
+ "HDA Intel", chip)) {
+ printk(KERN_ERR "hda-intel: unable to grab IRQ %d, "
+ "disabling device\n", chip->pci->irq);
+ if (do_disconnect)
+ snd_card_disconnect(chip->card);
+ return -1;
+ }
+ chip->irq = chip->pci->irq;
+ return 0;
+}
+

#ifdef CONFIG_PM
/*
@@ -1385,7 +1413,7 @@ static int azx_suspend(struct pci_dev *p
free_irq(chip->irq, chip);
chip->irq = -1;
}
- if (!disable_msi)
+ if (chip->msi)
pci_disable_msi(chip->pci);
pci_disable_device(pci);
pci_save_state(pci);
@@ -1407,16 +1435,11 @@ static int azx_resume(struct pci_dev *pc
return -EIO;
}
pci_set_master(pci);
- if (!disable_msi)
- pci_enable_msi(pci);
- if (request_irq(pci->irq, azx_interrupt, IRQF_DISABLED|IRQF_SHARED,
- "HDA Intel", chip)) {
- printk(KERN_ERR "hda-intel: unable to grab IRQ %d, "
- "disabling device\n", pci->irq);
- snd_card_disconnect(card);
+ if (chip->msi)
+ if (pci_enable_msi(pci) < 0)
+ chip->msi = 0;
+ if (azx_acquire_irq(chip, 1) < 0)
return -EIO;
- }
- chip->irq = pci->irq;
azx_init_chip(chip);
snd_hda_resume(chip->bus);
snd_power_change_state(card, SNDRV_CTL_POWER_D0);
@@ -1452,7 +1475,7 @@ static int azx_free(struct azx *chip)
synchronize_irq(chip->irq);
free_irq(chip->irq, (void*)chip);
}
- if (!disable_msi)
+ if (chip->msi)
pci_disable_msi(chip->pci);
if (chip->remap_addr)
iounmap(chip->remap_addr);
@@ -1508,6 +1531,7 @@ static int __devinit azx_create(struct s
chip->pci = pci;
chip->irq = -1;
chip->driver_type = driver_type;
+ chip->msi = !disable_msi;

chip->position_fix = position_fix;
chip->single_cmd = single_cmd;
@@ -1537,16 +1561,14 @@ static int __devinit azx_create(struct s
goto errout;
}

- if (!disable_msi)
- pci_enable_msi(pci);
-
- if (request_irq(pci->irq, azx_interrupt, IRQF_DISABLED|IRQF_SHARED,
- "HDA Intel", (void*)chip)) {
- snd_printk(KERN_ERR SFX "unable to grab IRQ %d\n", pci->irq);
+ if (chip->msi)
+ if (pci_enable_msi(pci) < 0)
+ chip->msi = 0;
+
+ if (azx_acquire_irq(chip, 0) < 0) {
err = -EBUSY;
goto errout;
}
- chip->irq = pci->irq;

pci_set_master(pci);
synchronize_irq(chip->irq);
-
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