Re: PCI: Add ALI M5229 comaptibility mode quirk

[Robert Hancock <hancockr@shaw.ca>]

Jeff Garzik wrote:
> Ben Dooks wrote:
>> The libata driver will not work with an M5229 set into native IDE
>> mode (the old drivers/pci one does) if the M5229 does not provide
>> it's own IRQ.
>>
>> The M5229 implementation embedded into the ALI M1543 uses the
>> M1543's ISA PIC to provide the interrupts and thus does not have
>> an valid PCI IRQ set. This quirk detects the abscence of IRQ and
>> sets the M5229 back into compatibility mode to use IRQs 14 and 15
>> so that libata works correctly.
>>
>> Note, I belive that the check for an valid interrupt line is
>> correct, I only have an M5229 in an ALI M1543 to check this
>> on. It would be useful to confirm that a M5229 with an valid IRQ
>> does not trigger this quirk.
>>
>> Signed-off-by: Ben Dooks <ben-linux@fluff.org>
>>
>> Index: linux-2.6.27-rc6-cats1/drivers/pci/quirks.c
>> ===================================================================
>> --- linux-2.6.27-rc6-cats1.orig/drivers/pci/quirks.c    2008-09-11 
>> 11:26:35.000000000 +0100
>> +++ linux-2.6.27-rc6-cats1/drivers/pci/quirks.c    2008-09-12 
>> 12:18:05.000000000 +0100
>> @@ -905,6 +905,34 @@ static void __devinit quirk_svwks_csb5id
>>  }
>>  DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, 
>> PCI_DEVICE_ID_SERVERWORKS_CSB5IDE, quirk_svwks_csb5ide);
>>  
>> +/* Some systems set the ALI M5229 in the ALI M1543 bridge to native 
>> mode,
>> + * which cannot be supported by the pata_ali.c driver (the old 
>> drivers/ide
>> + * makes a compatibility effort to change the IDE interrupts).
>> + */
>> +static void __devinit quirk_ali_ide_compatibility(struct pci_dev *pdev)
>> +{
>> +    u8 tmp;
>> +
>> +    /* pdev->irq and pdev->pin have yet to be initialised, so check
>> +     * by reading from the configuration header to see if we've got
>> +     * a valid interrupt line. */
>> +
>> +    pci_read_config_byte(pdev, PCI_INTERRUPT_LINE, &tmp);
>> +    if (tmp != 0xff)
>> +        return;
>> +
>> +    pci_read_config_byte(pdev, PCI_CLASS_PROG, &tmp);
>> +    if (tmp & 0x5) {
>> +        dev_info(&pdev->dev, "quirk: changing to IDE compatibility 
>> mode\n");
>> +
>> +        tmp &= ~0x05;
>> +        pdev->class &= ~0x05;
>> +        pci_write_config_byte(pdev, PCI_CLASS_PROG, tmp);
>> +    }
>> +}
>> +
>> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M5229, 
>> quirk_ali_ide_compatibility);
> 
> 
> This is a bit surprising, considering that libata works for all IDE mode 
> of other controllers...
> 
>     Jeff

Not if the controller has no native-mode IRQ assigned, it won't..