On Thu, Jan 11, 2018 at 6:48 PM, Ghannam, Yazen <[email protected]> wrote: >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On Behalf Of >> Rafael J. Wysocki >> Sent: Thursday, January 11, 2018 12:39 PM >> To: Ghannam, Yazen <[email protected]> >> Cc: ACPI Devel Maling List <[email protected]>; Linux Kernel Mailing >> List <[email protected]>; Linux PCI <[email protected]>; >> Rafael J. Wysocki <[email protected]>; Len Brown <[email protected]>; Bjorn >> Helgaas <[email protected]>; Borislav Petkov <[email protected]> >> Subject: Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear. >> >> On Thu, Jan 11, 2018 at 4:03 PM, Yazen Ghannam >> <[email protected]> wrote: >> > From: Yazen Ghannam <[email protected]> >> > >> > Currently, aer_service_init() checks if AER is available and that >> > Firmware First handling is not enabled. The _OSC request for AER is >> > not taken into account when deciding to enable AER in Linux. >> > >> > We should check that the _OSC control for AER is set. If it's not >> > then AER should be disabled. >> > >> > The _OSC control for AER is not requested when APEI Firmware First is >> > used, so the same condition applies. >> > >> > Mark AER as disabled if the _OSC request was not made or accepted. >> > >> > Remove redunant check for aer_acpi_firmware_first() when calling >> > aer_service_init(), since this is check is already included when >> > checking the _OSC control. >> > >> > Signed-off-by: Yazen Ghannam <[email protected]> >> > --- >> > drivers/acpi/pci_root.c | 3 +++ >> > drivers/pci/pcie/aer/aerdrv.c | 2 +- >> > 2 files changed, 4 insertions(+), 1 deletion(-) >> > >> > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c >> > index 6fc204a52493..19a625ed8de9 100644 >> > --- a/drivers/acpi/pci_root.c >> > +++ b/drivers/acpi/pci_root.c >> > @@ -512,6 +512,9 @@ static void negotiate_os_control(struct >> acpi_pci_root *root, int *no_aspm) >> > */ >> > *no_aspm = 1; >> > } >> > + >> > + if (!(requested & control & OSC_PCI_EXPRESS_AER_CONTROL)) >> >> One of the operators above needs to be a && I suppose? >> > > It's a 3-way bitwise AND to check that OSC_PCI_EXPRESS_AER_CONTROL is > set in both "requested" and "control". > > IOW, we check if AER was requested by the OS and that the platform > granted the request.
OK I'll queue this up if Bjorn doesn't object, unless Bjorn wants to apply it himself. Thanks, Rafael
