On 09/04/2015 06:14 PM, Frank Rowand wrote:
On 9/4/2015 12:12 PM, David Daney wrote:From: David Daney <david.daney@xxxxxxxxxx> 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.daney@xxxxxxxxxx> --- 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.
Since the current implementation *only ever* returns -ENODEV for PCI_INTERRUPT_PIN == 0, we could just document that behavior, and not hack up the APIs by adding a second return channel from the function.
The additional change on top of my patch would be to add a comment describing this behavior.
David Daney.
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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