From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Daney Subject: Re: [PATCH] of_pci_irq: Silence bogus "of_irq_parse_pci() failed ..." messages. Date: Fri, 04 Sep 2015 18:40:28 -0700 Message-ID: <55EA480C.6090306@gmail.com> References: <1441393926-23225-1-git-send-email-ddaney.cavm@gmail.com> <55EA41E3.5010103@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55EA41E3.5010103-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , Grant Likely , David Daney List-Id: devicetree@vger.kernel.org On 09/04/2015 06:14 PM, Frank Rowand wrote: > On 9/4/2015 12:12 PM, David Daney wrote: >> From: David Daney >> >> 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 >> --- >> 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 > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html