* [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
@ 2018-01-11 15:03 Yazen Ghannam
2018-01-11 17:38 ` Rafael J. Wysocki
2018-01-11 18:09 ` Bjorn Helgaas
0 siblings, 2 replies; 8+ messages in thread
From: Yazen Ghannam @ 2018-01-11 15:03 UTC (permalink / raw)
To: linux-acpi
Cc: linux-kernel, linux-pci, rjw, lenb, bhelgaas, bp, Yazen Ghannam
From: Yazen Ghannam <yazen.ghannam@amd.com>
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 <yazen.ghannam@amd.com>
---
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))
+ pci_no_aer();
}
static int acpi_pci_root_add(struct acpi_device *device,
diff --git a/drivers/pci/pcie/aer/aerdrv.c b/drivers/pci/pcie/aer/aerdrv.c
index 6ff5f5b4f5e6..39bb059777d0 100644
--- a/drivers/pci/pcie/aer/aerdrv.c
+++ b/drivers/pci/pcie/aer/aerdrv.c
@@ -374,7 +374,7 @@ static void aer_error_resume(struct pci_dev *dev)
*/
static int __init aer_service_init(void)
{
- if (!pci_aer_available() || aer_acpi_firmware_first())
+ if (!pci_aer_available())
return -ENXIO;
return pcie_port_service_register(&aerdriver);
}
--
2.14.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
2018-01-11 15:03 [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear Yazen Ghannam
@ 2018-01-11 17:38 ` Rafael J. Wysocki
2018-01-11 17:48 ` Ghannam, Yazen
2018-01-11 18:09 ` Bjorn Helgaas
1 sibling, 1 reply; 8+ messages in thread
From: Rafael J. Wysocki @ 2018-01-11 17:38 UTC (permalink / raw)
To: Yazen Ghannam
Cc: ACPI Devel Maling List, Linux Kernel Mailing List, Linux PCI,
Rafael J. Wysocki, Len Brown, Bjorn Helgaas, Borislav Petkov
On Thu, Jan 11, 2018 at 4:03 PM, Yazen Ghannam <Yazen.Ghannam@amd.com> wrote:
> From: Yazen Ghannam <yazen.ghannam@amd.com>
>
> 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 <yazen.ghannam@amd.com>
> ---
> 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?
> + pci_no_aer();
> }
>
> static int acpi_pci_root_add(struct acpi_device *device,
> diff --git a/drivers/pci/pcie/aer/aerdrv.c b/drivers/pci/pcie/aer/aerdrv.c
> index 6ff5f5b4f5e6..39bb059777d0 100644
> --- a/drivers/pci/pcie/aer/aerdrv.c
> +++ b/drivers/pci/pcie/aer/aerdrv.c
> @@ -374,7 +374,7 @@ static void aer_error_resume(struct pci_dev *dev)
> */
> static int __init aer_service_init(void)
> {
> - if (!pci_aer_available() || aer_acpi_firmware_first())
> + if (!pci_aer_available())
> return -ENXIO;
> return pcie_port_service_register(&aerdriver);
> }
> --
^ permalink raw reply [flat|nested] 8+ messages in thread
* RE: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
2018-01-11 17:38 ` Rafael J. Wysocki
@ 2018-01-11 17:48 ` Ghannam, Yazen
0 siblings, 0 replies; 8+ messages in thread
From: Ghannam, Yazen @ 2018-01-11 17:48 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: ACPI Devel Maling List, Linux Kernel Mailing List, Linux PCI,
Rafael J. Wysocki, Len Brown, Bjorn Helgaas, Borislav Petkov
> -----Original Message-----
> From: rjwysocki@gmail.com [mailto:rjwysocki@gmail.com] On Behalf Of
> Rafael J. Wysocki
> Sent: Thursday, January 11, 2018 12:39 PM
> To: Ghannam, Yazen <Yazen.Ghannam@amd.com>
> Cc: ACPI Devel Maling List <linux-acpi@vger.kernel.org>; Linux Kernel Mailing
> List <linux-kernel@vger.kernel.org>; Linux PCI <linux-pci@vger.kernel.org>;
> Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Bjorn
> Helgaas <bhelgaas@google.com>; Borislav Petkov <bp@suse.de>
> Subject: Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
>
> On Thu, Jan 11, 2018 at 4:03 PM, Yazen Ghannam
> <Yazen.Ghannam@amd.com> wrote:
> > From: Yazen Ghannam <yazen.ghannam@amd.com>
> >
> > 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 <yazen.ghannam@amd.com>
> > ---
> > 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.
Thanks,
Yazen
^ permalink raw reply [flat|nested] 8+ messages in thread
* RE: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
@ 2018-01-11 17:48 ` Ghannam, Yazen
0 siblings, 0 replies; 8+ messages in thread
From: Ghannam, Yazen @ 2018-01-11 17:48 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: ACPI Devel Maling List, Linux Kernel Mailing List, Linux PCI,
Rafael J. Wysocki, Len Brown, Bjorn Helgaas, Borislav Petkov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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
2018-01-11 17:48 ` Ghannam, Yazen
(?)
@ 2018-01-11 18:03 ` Rafael J. Wysocki
2018-01-11 19:04 ` Borislav Petkov
-1 siblings, 1 reply; 8+ messages in thread
From: Rafael J. Wysocki @ 2018-01-11 18:03 UTC (permalink / raw)
To: Ghannam, Yazen
Cc: Rafael J. Wysocki, ACPI Devel Maling List,
Linux Kernel Mailing List, Linux PCI, Rafael J. Wysocki,
Len Brown, Bjorn Helgaas, Borislav Petkov
On Thu, Jan 11, 2018 at 6:48 PM, Ghannam, Yazen <Yazen.Ghannam@amd.com> wrote:
>> -----Original Message-----
>> From: rjwysocki@gmail.com [mailto:rjwysocki@gmail.com] On Behalf Of
>> Rafael J. Wysocki
>> Sent: Thursday, January 11, 2018 12:39 PM
>> To: Ghannam, Yazen <Yazen.Ghannam@amd.com>
>> Cc: ACPI Devel Maling List <linux-acpi@vger.kernel.org>; Linux Kernel Mailing
>> List <linux-kernel@vger.kernel.org>; Linux PCI <linux-pci@vger.kernel.org>;
>> Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Bjorn
>> Helgaas <bhelgaas@google.com>; Borislav Petkov <bp@suse.de>
>> Subject: Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
>>
>> On Thu, Jan 11, 2018 at 4:03 PM, Yazen Ghannam
>> <Yazen.Ghannam@amd.com> wrote:
>> > From: Yazen Ghannam <yazen.ghannam@amd.com>
>> >
>> > 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 <yazen.ghannam@amd.com>
>> > ---
>> > 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
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
2018-01-11 15:03 [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear Yazen Ghannam
2018-01-11 17:38 ` Rafael J. Wysocki
@ 2018-01-11 18:09 ` Bjorn Helgaas
1 sibling, 0 replies; 8+ messages in thread
From: Bjorn Helgaas @ 2018-01-11 18:09 UTC (permalink / raw)
To: Yazen Ghannam
Cc: linux-acpi, linux-kernel, linux-pci, rjw, lenb, bhelgaas, bp
On Thu, Jan 11, 2018 at 09:03:16AM -0600, Yazen Ghannam wrote:
> From: Yazen Ghannam <yazen.ghannam@amd.com>
>
> 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.
s/redunant/redundant/
The concept seems right to me. Please add a citation to the relevant spec
section. I think this is somewhere in the PCI Firmware spec.
> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> ---
> 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))
> + pci_no_aer();
> }
>
> static int acpi_pci_root_add(struct acpi_device *device,
> diff --git a/drivers/pci/pcie/aer/aerdrv.c b/drivers/pci/pcie/aer/aerdrv.c
> index 6ff5f5b4f5e6..39bb059777d0 100644
> --- a/drivers/pci/pcie/aer/aerdrv.c
> +++ b/drivers/pci/pcie/aer/aerdrv.c
> @@ -374,7 +374,7 @@ static void aer_error_resume(struct pci_dev *dev)
> */
> static int __init aer_service_init(void)
> {
> - if (!pci_aer_available() || aer_acpi_firmware_first())
> + if (!pci_aer_available())
> return -ENXIO;
> return pcie_port_service_register(&aerdriver);
> }
> --
> 2.14.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
2018-01-11 18:03 ` Rafael J. Wysocki
@ 2018-01-11 19:04 ` Borislav Petkov
2018-01-12 0:28 ` Rafael J. Wysocki
0 siblings, 1 reply; 8+ messages in thread
From: Borislav Petkov @ 2018-01-11 19:04 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Ghannam, Yazen, ACPI Devel Maling List,
Linux Kernel Mailing List, Linux PCI, Rafael J. Wysocki,
Len Brown, Bjorn Helgaas
On Thu, Jan 11, 2018 at 07:03:23PM +0100, Rafael J. Wysocki wrote:
> >> > + 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
This definitely needs a comment - people will keep tripping over this.
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
2018-01-11 19:04 ` Borislav Petkov
@ 2018-01-12 0:28 ` Rafael J. Wysocki
0 siblings, 0 replies; 8+ messages in thread
From: Rafael J. Wysocki @ 2018-01-12 0:28 UTC (permalink / raw)
To: Borislav Petkov
Cc: Rafael J. Wysocki, Ghannam, Yazen, ACPI Devel Maling List,
Linux Kernel Mailing List, Linux PCI, Rafael J. Wysocki,
Len Brown, Bjorn Helgaas
On Thu, Jan 11, 2018 at 8:04 PM, Borislav Petkov <bp@suse.de> wrote:
> On Thu, Jan 11, 2018 at 07:03:23PM +0100, Rafael J. Wysocki wrote:
>> >> > + 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
>
> This definitely needs a comment - people will keep tripping over this.
Fair enough.
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-01-12 0:28 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-01-11 15:03 [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear Yazen Ghannam
2018-01-11 17:38 ` Rafael J. Wysocki
2018-01-11 17:48 ` Ghannam, Yazen
2018-01-11 17:48 ` Ghannam, Yazen
2018-01-11 18:03 ` Rafael J. Wysocki
2018-01-11 19:04 ` Borislav Petkov
2018-01-12 0:28 ` Rafael J. Wysocki
2018-01-11 18:09 ` Bjorn Helgaas
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.