Messages in this thread | | | Date | Fri, 3 Nov 2023 16:58:28 +0200 | From | Andy Shevchenko <> | Subject | Re: [PATCH v2] mfd: intel-lpss: Fix IRQ check |
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On Fri, Nov 03, 2023 at 08:41:40AM +0200, Mika Westerberg wrote: > On Thu, Nov 02, 2023 at 02:38:31PM +0200, Andy Shevchenko wrote: > > > > > > - if (!info || !info->mem || info->irq <= 0) > > > > > > + if (!info || !info->mem) > > > > > > > > > > This check (info->irq <= 0) covers both "invalid" interrupt numbers > > > > > (that's the negative errno and 0 as no interrupt) so I don't see how > > > > > this change makes it any better and the changelog does not clarify it > > > > > either. > > > > > > > > It makes sense. The IRQ here may not be 0. We should actually fix > > > > the PCI code to guarantee that (platform_get_irq() guarantees that > > > > in platform driver). > > > > > > Yeah but I mean the check above handles any "invalid" interrupt number > > > just fine regardless. I don't see any point changing that. > > > > The point is to have proper error code to be returned. Currently it's shadowed > > in this check. > > Looking at this more, this patch actually introduces a bug. > > We pass pci_dev->irq from intel-lpss-pci.c and that comes directly from > PCI core that assigns it in pci_read_irq(). This value is unsigned int > for starters so it is not designed to contain an error code, secondly it > can be 0 meaning "no IRQ" either if is SRIOV device or the interrupt > line is not assigned. I actually think SRIOV is a possibility for future > LPSS devices so we should be dealing with this properly.
I could argue that this patch _reveals_ the bug in PCI that needs to be addressed.
-- With Best Regards, Andy Shevchenko
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