[PATCH] Update MCP55 quirk to not affect non HyperTransport variants

[PATCH] Update MCP55 quirk to not affect non HyperTransport variants

[Neil Horman]

I wrote this quirk awhile ago to properly setup MCP55 chips on hypertransport
busses so that interrupts reached whatever cpu happend to boot the kdump kernel.
while that works well, it was recently shown to me that a a non-hypertransport
variant of the MCP55 exists, and on those system the register that this quirk
manipulates causes hangs if you write to it.  Since the quirk was only meant to
handle errors found on MCP55 chips that have a HT interface, this patch adds a
filter to make sure the chip is an HT capable before making the needed register
adjustment.  This lets the broken MCP55s work with kdump while not breaking the
non-HT variants.

Resolves https://bugzilla.kernel.org/show_bug.cgi?id=23952

Tested successfully by the reporter and myself.

Reported-by: Mathieu Bérard <mathieu@mberard.eu>
CC: linux-pci@vger.kernel.org
CC: kexec@lists.infradead.org
CC: Vivek Goyal <vgoyal@redhat.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
---
 drivers/pci/quirks.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 6f9350c..313c0bd 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2329,6 +2329,9 @@ static void __devinit nvbridge_check_legacy_irq_routing(struct pci_dev *dev)
 {
 	u32 cfg;
 
+	if (!pci_find_capability(dev, PCI_CAP_ID_HT))
+		return;
+
 	pci_read_config_dword(dev, 0x74, &cfg);
 
 	if (cfg & ((1 << 2) | (1 << 15))) {
-- 
1.7.2.3

Re: [PATCH] Update MCP55 quirk to not affect non HyperTransport variants

[Vivek Goyal]

On Wed, Dec 08, 2010 at 09:47:48AM -0500, Neil Horman wrote:
> I wrote this quirk awhile ago to properly setup MCP55 chips on hypertransport
> busses so that interrupts reached whatever cpu happend to boot the kdump kernel.
> while that works well, it was recently shown to me that a a non-hypertransport
> variant of the MCP55 exists, and on those system the register that this quirk
> manipulates causes hangs if you write to it.  Since the quirk was only meant to
> handle errors found on MCP55 chips that have a HT interface, this patch adds a
> filter to make sure the chip is an HT capable before making the needed register
> adjustment.  This lets the broken MCP55s work with kdump while not breaking the
> non-HT variants.
> 

So Neil, with non hypertransport MCP55s, interrupts are delivered to
all the cpus and seond kernel still boots?

Acked-by: Vivek Goyal <vgoyal@redhat.com>

Thanks
Vivek

> Resolves https://bugzilla.kernel.org/show_bug.cgi?id=23952
> 
> Tested successfully by the reporter and myself.
> 
> Reported-by: Mathieu Bérard <mathieu@mberard.eu>
> CC: linux-pci@vger.kernel.org
> CC: kexec@lists.infradead.org
> CC: Vivek Goyal <vgoyal@redhat.com>
> CC: Jesse Barnes <jbarnes@virtuousgeek.org>
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> ---
>  drivers/pci/quirks.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 6f9350c..313c0bd 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -2329,6 +2329,9 @@ static void __devinit nvbridge_check_legacy_irq_routing(struct pci_dev *dev)
>  {
>  	u32 cfg;
>  
> +	if (!pci_find_capability(dev, PCI_CAP_ID_HT))
> +		return;
> +
>  	pci_read_config_dword(dev, 0x74, &cfg);
>  
>  	if (cfg & ((1 << 2) | (1 << 15))) {
> -- 
> 1.7.2.3

Re: [PATCH] Update MCP55 quirk to not affect non HyperTransport variants

[Neil Horman]

On Wed, Dec 08, 2010 at 11:44:23AM -0500, Vivek Goyal wrote:
> On Wed, Dec 08, 2010 at 09:47:48AM -0500, Neil Horman wrote:
> > I wrote this quirk awhile ago to properly setup MCP55 chips on hypertransport
> > busses so that interrupts reached whatever cpu happend to boot the kdump kernel.
> > while that works well, it was recently shown to me that a a non-hypertransport
> > variant of the MCP55 exists, and on those system the register that this quirk
> > manipulates causes hangs if you write to it.  Since the quirk was only meant to
> > handle errors found on MCP55 chips that have a HT interface, this patch adds a
> > filter to make sure the chip is an HT capable before making the needed register
> > adjustment.  This lets the broken MCP55s work with kdump while not breaking the
> > non-HT variants.
> > 
> 
> So Neil, with non hypertransport MCP55s, interrupts are delivered to
> all the cpus and seond kernel still boots?
> 
I cannot guarantee that.  All that I can guarantee is that, on MCP55 chips
without hypertransport capability, the register which is used to configure
interrupt delivery is either non-existant, or different in such a way that
writing to it results in a hang on the boot of the initial kernel.  So this
quirk has no effect on kdumps behavior regardless of the interrupt delivery
behavior on such variants of the chip.  I would presume however, given that this
register is so different that interrupts would be delivered to all cpus, as one
would expect.  Mathieu, since you have the affected hardware, could you attempt
to preform a kexec operation and tell us for certain?  Thanks!
Neil

> Acked-by: Vivek Goyal <vgoyal@redhat.com>
> 
> Thanks
> Vivek
> 
> > Resolves https://bugzilla.kernel.org/show_bug.cgi?id=23952
> > 
> > Tested successfully by the reporter and myself.
> > 
> > Reported-by: Mathieu Bérard <mathieu@mberard.eu>
> > CC: linux-pci@vger.kernel.org
> > CC: kexec@lists.infradead.org
> > CC: Vivek Goyal <vgoyal@redhat.com>
> > CC: Jesse Barnes <jbarnes@virtuousgeek.org>
> > Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> > ---
> >  drivers/pci/quirks.c |    3 +++
> >  1 files changed, 3 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > index 6f9350c..313c0bd 100644
> > --- a/drivers/pci/quirks.c
> > +++ b/drivers/pci/quirks.c
> > @@ -2329,6 +2329,9 @@ static void __devinit nvbridge_check_legacy_irq_routing(struct pci_dev *dev)
> >  {
> >  	u32 cfg;
> >  
> > +	if (!pci_find_capability(dev, PCI_CAP_ID_HT))
> > +		return;
> > +
> >  	pci_read_config_dword(dev, 0x74, &cfg);
> >  
> >  	if (cfg & ((1 << 2) | (1 << 15))) {
> > -- 
> > 1.7.2.3
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

Re: [PATCH] Update MCP55 quirk to not affect non HyperTransport variants

[Andrew Morton]

On Wed,  8 Dec 2010 09:47:48 -0500
Neil Horman <nhorman@tuxdriver.com> wrote:

> I wrote this quirk awhile ago to properly setup MCP55 chips on hypertransport
> busses so that interrupts reached whatever cpu happend to boot the kdump kernel.
> while that works well, it was recently shown to me that a a non-hypertransport
> variant of the MCP55 exists, and on those system the register that this quirk
> manipulates causes hangs if you write to it.  Since the quirk was only meant to
> handle errors found on MCP55 chips that have a HT interface, this patch adds a
> filter to make sure the chip is an HT capable before making the needed register
> adjustment.  This lets the broken MCP55s work with kdump while not breaking the
> non-HT variants.
> 
> Resolves https://bugzilla.kernel.org/show_bug.cgi?id=23952
> 
> Tested successfully by the reporter and myself.
> 
> Reported-by: Mathieu B__rard <mathieu@mberard.eu>
> CC: linux-pci@vger.kernel.org
> CC: kexec@lists.infradead.org
> CC: Vivek Goyal <vgoyal@redhat.com>
> CC: Jesse Barnes <jbarnes@virtuousgeek.org>
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>

That needed a Cc:<stable@kernel.org> as well.  Please don't forget to
remember -stable.

Re: [PATCH] Update MCP55 quirk to not affect non HyperTransport variants

[Neil Horman]

On Thu, Dec 09, 2010 at 03:40:41PM -0800, Andrew Morton wrote:
> On Wed,  8 Dec 2010 09:47:48 -0500
> Neil Horman <nhorman@tuxdriver.com> wrote:
> 
> > I wrote this quirk awhile ago to properly setup MCP55 chips on hypertransport
> > busses so that interrupts reached whatever cpu happend to boot the kdump kernel.
> > while that works well, it was recently shown to me that a a non-hypertransport
> > variant of the MCP55 exists, and on those system the register that this quirk
> > manipulates causes hangs if you write to it.  Since the quirk was only meant to
> > handle errors found on MCP55 chips that have a HT interface, this patch adds a
> > filter to make sure the chip is an HT capable before making the needed register
> > adjustment.  This lets the broken MCP55s work with kdump while not breaking the
> > non-HT variants.
> > 
> > Resolves https://bugzilla.kernel.org/show_bug.cgi?id=23952
> > 
> > Tested successfully by the reporter and myself.
> > 
> > Reported-by: Mathieu B__rard <mathieu@mberard.eu>
> > CC: linux-pci@vger.kernel.org
> > CC: kexec@lists.infradead.org
> > CC: Vivek Goyal <vgoyal@redhat.com>
> > CC: Jesse Barnes <jbarnes@virtuousgeek.org>
> > Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> 
> That needed a Cc:<stable@kernel.org> as well.  Please don't forget to
> remember -stable.
Thanks, Cc'ing stable on the thread

> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 

Re: [PATCH] Update MCP55 quirk to not affect non HyperTransport variants

[Jesse Barnes]

On Wed,  8 Dec 2010 09:47:48 -0500
Neil Horman <nhorman@tuxdriver.com> wrote:

> I wrote this quirk awhile ago to properly setup MCP55 chips on hypertransport
> busses so that interrupts reached whatever cpu happend to boot the kdump kernel.
> while that works well, it was recently shown to me that a a non-hypertransport
> variant of the MCP55 exists, and on those system the register that this quirk
> manipulates causes hangs if you write to it.  Since the quirk was only meant to
> handle errors found on MCP55 chips that have a HT interface, this patch adds a
> filter to make sure the chip is an HT capable before making the needed register
> adjustment.  This lets the broken MCP55s work with kdump while not breaking the
> non-HT variants.
> 
> Resolves https://bugzilla.kernel.org/show_bug.cgi?id=23952
> 
> Tested successfully by the reporter and myself.

Applied to my for-linus branch, thanks.

-- 
Jesse Barnes, Intel Open Source Technology Center