On 9/4/2015 12:12 PM, David Daney wrote:
> From: David Daney <david.da...@cavium.com>
>
> It is perfectly legitimate for a PCI device to have an
> PCI_INTERRUPT_PIN value of zero. This happens if the device doesn't
> use interrupts, or on PCIe devices, where only MSI/MSI-X are
> supported.
>
> Silence the annoying "of_irq_parse_pci() failed with rc=-19" error
> messages by making them conditional on !-ENODEV (which can only be
> produced in the PCI_INTERRUPT_PIN == 0 case).
>
> Signed-off-by: David Daney <david.da...@cavium.com>
> ---
> drivers/of/of_pci_irq.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/of/of_pci_irq.c b/drivers/of/of_pci_irq.c
> index 1710d9d..33d242a 100644
> --- a/drivers/of/of_pci_irq.c
> +++ b/drivers/of/of_pci_irq.c
> @@ -106,7 +106,9 @@ int of_irq_parse_and_map_pci(const struct pci_dev *dev,
> u8 slot, u8 pin)
>
> ret = of_irq_parse_pci(dev, &oirq);
> if (ret) {
> - dev_err(&dev->dev, "of_irq_parse_pci() failed with rc=%d\n",
> ret);
> + if (ret != -ENODEV)
> + dev_err(&dev->dev,
> + "of_irq_parse_pci() failed with rc=%d\n", ret);
> return 0; /* Proper return code 0 == NO_IRQ */
> }
>
>
It is not safe to assume that the functions that of_irq_parse_pci() calls
will never be modified to return -ENODEV, thus resulting in of_irq_parse_pci()
returning -ENODEV for a reason other than PCI_INTERRUPT_PIN == 0.
A more robust solution would be something like:
(1) Change of_irq_parse_pci() to _of_irq_parse_pci(), adding an argument and
use it to report the case of PCI_INTERRUPT_PIN == 0.
static int _of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args
*out_irq, int *no_pin)
{
...
*no_pin = 0;
...
/* No pin, exit */
if (pin == 0) {
*no_pin = 1;
return -ENODEV;
}
...
int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args
*out_irq)
{
int no_pin;
return _of_irq_parse_pci(pdev, out_irq, &no_pin)
}
(2) Then the fix to of_irq_parse_and_map_pci() would be:
+ int no_pin;
> ret = of_irq_parse_pci(dev, &oirq, &no_pin);
> if (ret) {
> - dev_err(&dev->dev, "of_irq_parse_pci() failed with rc=%d\n",
> ret);
> + if (!no_pin)
> + dev_err(&dev->dev,
> + "of_irq_parse_pci() failed with rc=%d\n", ret);
> return 0; /* Proper return code 0 == NO_IRQ */
> }
I'm not sure I like my solution, there might be a better way.
I also noticed another bug while looking at of_irq_parse_pci(). It returns
the non-zero return value from pci_read_config_byte(). But that value is
one of the PCI function error values from include/linux/pci.h, such as:
#define PCIBIOS_BAD_REGISTER_NUMBER 0x87
instead of a negative errno.
-Frank
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