From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <1521560965.23017.68.camel@linux.intel.com> Subject: Re: [PATCH v3 1/2] x86/PCI: Fix a potential regression when use dmi_get_bios_year() From: Andy Shevchenko To: Jean Delvare Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, "Rafael J . Wysocki" , linux-acpi@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , x86@kernel.org, Lukas Wunner Date: Tue, 20 Mar 2018 17:49:25 +0200 In-Reply-To: <20180320163258.5ac39580@endymion> References: <20180320135410.11627-1-andriy.shevchenko@linux.intel.com> <20180320135410.11627-2-andriy.shevchenko@linux.intel.com> <20180320163258.5ac39580@endymion> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-acpi-owner@vger.kernel.org List-ID: On Tue, 2018-03-20 at 16:32 +0100, Jean Delvare wrote: > Hi Andy, > > On Tue, 20 Mar 2018 15:54:09 +0200, Andy Shevchenko wrote: > > dmi_get_bios_year() may return 0 when it is incapable to parse > > the BIOS date string. Previously this has been checked in > > pci_acpi_crs_quirks(). > > > > Update the code to restore old behaviour. > > When fixing a regression, a good practice is to tag the fix commit as > such: > > Fixes: 69c42d493db4 ("x86/pci: Simplify code by using the new > dmi_get_bios_year() helper") Someone (perhaps Ingo) told me that Fixes doesn't make much sense if the fixing commit is not yet in vanilla. Since it's supposed to go via tip tree I would like to hear Ingo's opinion before adding this line to the patch. > > Reported-by: Jean Delvare > > Signed-off-by: Andy Shevchenko > > --- > > arch/x86/pci/acpi.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c > > index 00e60de30328..5559dcaddd5e 100644 > > --- a/arch/x86/pci/acpi.c > > +++ b/arch/x86/pci/acpi.c > > @@ -140,7 +140,9 @@ static const struct dmi_system_id > > pci_crs_quirks[] __initconst = { > > > > void __init pci_acpi_crs_quirks(void) > > { > > - if ((dmi_get_bios_year() < 2008) && (iomem_resource.end <= > > 0xffffffff)) > > + int year = dmi_get_bios_year(); > > + > > + if (year >= 0 && year < 2008 && iomem_resource.end <= > > 0xffffffff) > > pci_use_crs = false; > > > > dmi_check_system(pci_crs_quirks); > > This works with the non-inline version of dmi_get_bios_year() > introduced by patch 2/2 of this series. However the inline version of > this function would return 0 on error, which makes the condition above > always true. > > The patches need to be applied in the opposite order, or the test > above > should be changed to "year > 0". Err... Yes, I use to have them in opposite order, but at some point I decided to reverse and forgot about the condition. So, you are right, it needs to be applied in reversed order. > > Reviewed-by: Jean Delvare > -- Andy Shevchenko Intel Finland Oy