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

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Message-ID: <20101208164423.GH31703@redhat.com>
Date:	Wed, 8 Dec 2010 11:44:23 -0500
From:	Vivek Goyal <vgoyal@...hat.com>
To:	Neil Horman <nhorman@...driver.com>
Cc:	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	kexec@...ts.infradead.org, Jesse Barnes <jbarnes@...tuousgeek.org>
Subject: Re: [PATCH] Update MCP55 quirk to not affect non HyperTransport
 variants

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@...hat.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@...rard.eu>
> CC: linux-pci@...r.kernel.org
> CC: kexec@...ts.infradead.org
> CC: Vivek Goyal <vgoyal@...hat.com>
> CC: Jesse Barnes <jbarnes@...tuousgeek.org>
> Signed-off-by: Neil Horman <nhorman@...driver.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
--
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