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Violators will be prosecuted for from ; Fri, 9 Dec 2016 16:19:17 -0200 Subject: Re: [PATCH v2] of/irq: improve error report on irq discovery process failure To: Rob Herring References: <1480946356-16778-1-git-send-email-gpiccoli@linux.vnet.ibm.com> <5845B980.2030609@linux.vnet.ibm.com> Cc: "linux-pci@vger.kernel.org" , "devicetree@vger.kernel.org" , linuxppc-dev , Mark Rutland , Benjamin Herrenschmidt , Frank Rowand , Marc Zyngier From: "Guilherme G. Piccoli" Date: Fri, 9 Dec 2016 16:19:08 -0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Message-Id: <584AF59C.50500@linux.vnet.ibm.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On 12/09/2016 02:25 PM, Rob Herring wrote: > On Mon, Dec 5, 2016 at 1:01 PM, Guilherme G. Piccoli > wrote: >> On 12/05/2016 12:28 PM, Rob Herring wrote: >>> On Mon, Dec 5, 2016 at 7:59 AM, Guilherme G. Piccoli >>> wrote: >>>> On PowerPC machines some PCI slots might not have level triggered >>>> interrupts capability (also know as level signaled interrupts), >>>> leading of_irq_parse_pci() to complain by presenting error messages >>>> on the kernel log - in this case, the properties "interrupt-map" and >>>> "interrupt-map-mask" are not present on device's node in the device >>>> tree. >>>> >>>> This patch introduces a different message for this specific case, >>>> and also reduces its level from error to warning. Besides, we warn >>>> (once) that possibly some PCI slots on the system have no level >>>> triggered interrupts available. >>>> We changed some error return codes too on function of_irq_parse_raw() >>>> in order other failure's cases can be presented in a more precise way. >>>> >>>> Before this patch, when an adapter was plugged in a slot without level >>>> interrupts capabilitiy on PowerPC, we saw a generic error message >>>> like this: >>>> >>>> [54.239] pci 002d:70:00.0: of_irq_parse_pci() failed with rc=-22 >>>> >>>> Now, with this applied, we see the following specific message: >>>> >>>> [16.154] pci 0014:60:00.1: of_irq_parse_pci: no interrupt-map found, >>>> INTx interrupts not available >>>> >>>> Finally, we standardize the error path in of_irq_parse_raw() by always >>>> taking the fail path instead of returning directly from the loop. >>>> >>>> Signed-off-by: Guilherme G. Piccoli >>>> --- >>>> >>>> v2: >>>> * Changed function return code to always return negative values; >>> >>> Are you sure this is safe? This is tricky because of differing values >>> of NO_IRQ (0 or -1). >> >> Thanks Rob, but this is purely bad wording from myself. I'm sorry - I >> meant to say that I changed only my positive return code (that was >> suggested to be removed in the prior revision) to negative return code! >> >> So, I changed only code I added myself in v1 =) >> >> >>> >>>> * Improved/simplified warning outputs; >>>> * Changed some return codes and some error paths in of_irq_parse_raw() >>>> in order to be more precise/consistent; >>> >>> This too could have some side effects on callers. >>> >>> Not saying don't do these changes, just need some assurances this has >>> been considered. >> >> Thanks for your attention. I performed a quick investigation before >> changing this, all the places that use the return values are just >> getting "true/false" information from that, meaning they just are >> comparing to 0 basically. So change -EINVAL to -ENOENT wouldn't hurt any >> user of these return values, it'll only become more informative IMHO. >> >> Now, regarding the only error path that was changed: for some reason, >> this was the only place in which we didn't goto fail label in case of >> failure - it was added by a legacy commit from Ben, dated from 2006: >> 006b64de60 ("[POWERPC] Make OF irq map code detect more error cases"). >> Then it was carried by Grant Likely's commit 7dc2e1134a ("of/irq: merge >> irq mapping code"), 6-year old commit. >> I wasn't able to imagine a scenario in which changing this would break >> something; I believe the change improve consistency, but I'd remove it >> if you or somebody else thinks it worth be removed. > > Okay. It's a bit late for 4.10 now and want this to be in -next for a > while, so I'll queue it after the merge window. > OK, perfect! Thanks Rob Cheers, Guilherme > Rob >