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Subject[PATCH] Unbreak MSI on ATI devices
Hello Jeff,
I'm using second patch below for couple of months to get MSI on all
devices present on my notebook which are MSI capable (except IDE - notebook
uses IDE in legacy mode and seems unhappy with transition to native MSI-based
mode; maybe I could try do the job with libata now when I switched; and VGA, I
do not use dri...). All worked nicely until last sync, when I noticed that my
USB devices suddenly stopped working (it took me few weeks as I do not use USB
regulary).

After poking around I've found that problem is that at least ATI USB-HCDs
apply INTX enable even for MSI, despite warning in the PCI specification that
it should apply only to MSI (actually I have feeling that on these USB devices
disabling INTX in MSI mode drives their INTA# line active as when ohci1394
module got loaded kernel complained about interrupt being continuously
activated for no good reason (TI's 7421 is one of few MSI-incapable devices
in my box).

So my question is - what is real reason for disabling INTX when in MSI mode?
According to PCI spec it should not be needed, and it hurts at least chips
listed below:

00:13.0 0c03: 1002:4374 USB Controller: ATI Technologies Inc IXP SB400 USB Host Controller
00:13.1 0c03: 1002:4375 USB Controller: ATI Technologies Inc IXP SB400 USB Host Controller
00:13.2 0c03: 1002:4373 USB Controller: ATI Technologies Inc IXP SB400 USB2 Host Controller

I believe that these devices from same vendor accept disabling INTX while in MSI
fine (I did not notice problems with them even with INTX disabling code in msi.c):

00:14.5 0401: 1002:4370 (rev 02) Multimedia audio controller: ATI Technologies Inc IXP SB400 AC'97 Audio Controller (rev 02)
00:14.6 0703: 1002:4378 (rev 02) Modem: ATI Technologies Inc ATI SB400 - AC'97 Modem Controller (rev 02)

None of devices in the box assert INTX while in MSI even if INTX is enabled.


So I'd like to see first patch below accepted. If there are some devices which
require INTX disabling, then apparently decision whether to disable it or no
has to be moved to device drivers, or some blacklist/whitelist must be created...

I'm not sure about second one - I have it in my tree for months, but I run
that kernel only on hardware mentioned above, so it is probably too dangerous
until pci_enable_msi() gets answer whether MSI works or no always right.
Thanks,
Petr Vandrovec

/proc/interrupts after patch. Before patch *hci_hcd:usb* were at zero, IRQ21 was
stuck with IRQ count at 10000, and HCD complained about "Unlink after no-IRQ?".
CPU0
0: 140326 local-APIC-edge-fasteio timer
1: 10773 IO-APIC-edge i8042
8: 1 IO-APIC-edge rtc
12: 34498 IO-APIC-edge i8042
14: 34714 IO-APIC-edge libata
15: 82 IO-APIC-edge libata
16: 1 IO-APIC-fasteoi tifm_7xx1, yenta, sdhci:slot0, sdhci:slot1, sdhci:slot2
21: 265 IO-APIC-fasteoi acpi, ohci1394
22: 28973 IO-APIC-fasteoi ipw2200
216: 1 PCI-MSI-edge ATI IXP Modem
217: 1 PCI-MSI-edge ATI IXP
218: 2 PCI-MSI-edge ehci_hcd:usb3
219: 88 PCI-MSI-edge ohci_hcd:usb2
220: 1 PCI-MSI-edge ohci_hcd:usb1
221: 1 PCI-MSI-edge eth0
NMI: 0
LOC: 140293
ERR: 0
MIS: 0


Do not disable INTX in MSI mode. It breaks ATI USB HCDs (both OHCI and EHCI).

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>

diff -uprdN linux/drivers/pci/msi.c linux/drivers/pci/msi.c
--- linux/drivers/pci/msi.c 2006-12-16 13:34:52.000000000 -0800
+++ linux/drivers/pci/msi.c 2006-12-20 23:18:10.000000000 -0800
@@ -256,7 +256,7 @@ static void enable_msi_mode(struct pci_d
dev->msix_enabled = 1;
}

- pci_intx(dev, 0); /* disable intx */
+ pci_intx(dev, 1); /* enable intx, on some devices it affects MSI as well */
}

void disable_msi_mode(struct pci_dev *dev, int pos, int type)


Use MSI when available on USB HCDs and on ATI AC'97 hardware.

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>

diff -uprdN linux/drivers/usb/core/hcd-pci.c linux/drivers/usb/core/hcd-pci.c
--- linux/drivers/usb/core/hcd-pci.c 2006-12-16 13:34:57.000000000 -0800
+++ linux/drivers/usb/core/hcd-pci.c 2006-12-16 13:57:09.000000000 -0800
@@ -69,6 +69,7 @@ int usb_hcd_pci_probe (struct pci_dev *d

if (pci_enable_device (dev) < 0)
return -ENODEV;
+ pci_enable_msi(dev);
dev->current_state = PCI_D0;
dev->dev.power.power_state = PMSG_ON;

@@ -139,6 +140,7 @@ int usb_hcd_pci_probe (struct pci_dev *d
release_region (hcd->rsrc_start, hcd->rsrc_len);
err2:
usb_put_hcd (hcd);
+ pci_disable_msi (dev);
err1:
pci_disable_device (dev);
dev_err (&dev->dev, "init %s fail, %d\n", pci_name(dev), retval);
@@ -177,6 +179,7 @@ void usb_hcd_pci_remove (struct pci_dev
release_region (hcd->rsrc_start, hcd->rsrc_len);
}
usb_put_hcd (hcd);
+ pci_disable_msi(dev);
pci_disable_device(dev);
}
EXPORT_SYMBOL (usb_hcd_pci_remove);
@@ -391,6 +394,7 @@ int usb_hcd_pci_resume (struct pci_dev *
"can't re-enable after resume, %d!\n", retval);
return retval;
}
+ pci_enable_msi (dev);
pci_set_master (dev);
pci_restore_state (dev);

diff -uprdN linux/sound/pci/atiixp.c linux/sound/pci/atiixp.c
--- linux/sound/pci/atiixp.c 2006-12-16 13:35:47.000000000 -0800
+++ linux/sound/pci/atiixp.c 2006-12-16 13:57:09.000000000 -0800
@@ -60,6 +60,8 @@ MODULE_PARM_DESC(spdif_aclink, "S/PDIF o
/* just for backward compatibility */
static int enable;
module_param(enable, bool, 0444);
+static int msi;
+module_param(msi, bool, 0444);


/*
@@ -279,6 +281,8 @@ struct atiixp {

int spdif_over_aclink; /* passed from the module option */
struct mutex open_mutex; /* playback open mutex */
+
+ int have_msi;
};


@@ -1442,6 +1446,11 @@ static int snd_atiixp_suspend(struct pci
snd_atiixp_aclink_down(chip);
snd_atiixp_chip_stop(chip);

+ if (chip->have_msi) {
+ pci_disable_msi(pci);
+ } else {
+ pci_intx(pci, 0);
+ }
pci_disable_device(pci);
pci_save_state(pci);
pci_set_power_state(pci, pci_choose_state(pci, state));
@@ -1463,6 +1472,11 @@ static int snd_atiixp_resume(struct pci_
return -EIO;
}
pci_set_master(pci);
+ if (chip->have_msi) {
+ pci_enable_msi(pci);
+ } else {
+ pci_intx(pci, 1);
+ }

snd_atiixp_aclink_reset(chip);
snd_atiixp_chip_start(chip);
@@ -1532,6 +1546,11 @@ static int snd_atiixp_free(struct atiixp
if (chip->remap_addr)
iounmap(chip->remap_addr);
pci_release_regions(chip->pci);
+ if (chip->have_msi) {
+ pci_disable_msi(chip->pci);
+ } else {
+ pci_intx(chip->pci, 0);
+ }
pci_disable_device(chip->pci);
kfree(chip);
return 0;
@@ -1583,6 +1602,9 @@ static int __devinit snd_atiixp_create(s
return -EIO;
}

+ if (msi && pci_enable_msi(pci) == 0) {
+ chip->have_msi = 1;
+ }
if (request_irq(pci->irq, snd_atiixp_interrupt, IRQF_DISABLED|IRQF_SHARED,
card->shortname, chip)) {
snd_printk(KERN_ERR "unable to grab IRQ %d\n", pci->irq);
@@ -1591,6 +1613,9 @@ static int __devinit snd_atiixp_create(s
}
chip->irq = pci->irq;
pci_set_master(pci);
+ if (!chip->have_msi) {
+ pci_intx(pci, 1);
+ }
synchronize_irq(chip->irq);

if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
diff -uprdN linux/sound/pci/atiixp_modem.c linux/sound/pci/atiixp_modem.c
--- linux/sound/pci/atiixp_modem.c 2006-12-16 13:35:47.000000000 -0800
+++ linux/sound/pci/atiixp_modem.c 2006-12-16 13:57:09.000000000 -0800
@@ -54,6 +54,8 @@ MODULE_PARM_DESC(ac97_clock, "AC'97 code
/* just for backward compatibility */
static int enable;
module_param(enable, bool, 0444);
+static int msi;
+module_param(msi, bool, 0444);


/*
@@ -257,6 +259,8 @@ struct atiixp_modem {

int spdif_over_aclink; /* passed from the module option */
struct mutex open_mutex; /* playback open mutex */
+
+ int have_msi;
};


@@ -1128,6 +1132,11 @@ static int snd_atiixp_suspend(struct pci
snd_atiixp_aclink_down(chip);
snd_atiixp_chip_stop(chip);

+ if (chip->have_msi) {
+ pci_disable_msi(pci);
+ } else {
+ pci_intx(pci, 0);
+ }
pci_disable_device(pci);
pci_save_state(pci);
pci_set_power_state(pci, pci_choose_state(pci, state));
@@ -1149,6 +1158,11 @@ static int snd_atiixp_resume(struct pci_
return -EIO;
}
pci_set_master(pci);
+ if (chip->have_msi) {
+ pci_enable_msi(pci);
+ } else {
+ pci_intx(pci, 1);
+ }

snd_atiixp_aclink_reset(chip);
snd_atiixp_chip_start(chip);
@@ -1204,6 +1218,11 @@ static int snd_atiixp_free(struct atiixp
free_irq(chip->irq, chip);
if (chip->remap_addr)
iounmap(chip->remap_addr);
+ if (chip->have_msi) {
+ pci_disable_msi(chip->pci);
+ } else {
+ pci_intx(chip->pci, 0);
+ }
pci_release_regions(chip->pci);
pci_disable_device(chip->pci);
kfree(chip);
@@ -1255,7 +1274,9 @@ static int __devinit snd_atiixp_create(s
snd_atiixp_free(chip);
return -EIO;
}
-
+ if (msi && pci_enable_msi(pci) == 0) {
+ chip->have_msi = 1;
+ }
if (request_irq(pci->irq, snd_atiixp_interrupt, IRQF_DISABLED|IRQF_SHARED,
card->shortname, chip)) {
snd_printk(KERN_ERR "unable to grab IRQ %d\n", pci->irq);
@@ -1264,6 +1285,9 @@ static int __devinit snd_atiixp_create(s
}
chip->irq = pci->irq;
pci_set_master(pci);
+ if (!chip->have_msi) {
+ pci_intx(pci, 1);
+ }
synchronize_irq(chip->irq);

if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
-
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