Re: [PATCH] PCI / PCIe: Introduce command line option to disableARI

From: Randy Dunlap
Date: Wed Feb 29 2012 - 17:33:15 EST


On 02/29/2012 02:09 PM, Rafael J. Wysocki wrote:

> From: Rafael J. Wysocki <rjw@xxxxxxx>
>
> There are PCIe devices on the market that report ARI support but
> then fail to initialize correctly when ARI is actually used. This
> leads to situations in which kernels 2.6.34 and newer fail to handle
> systems where the previous kernels worked without any apparent
> problems. Unfortunately, it is currently unknown how many such
> devices are there.
>
> For this reason, introduce a new kernel command line option,
> pci=noari, allowing users to disable PCIe ARI altogether if they
> see problems with PCIe device initialization.
>
> Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> ---
> drivers/pci/pci.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> Index: linux/drivers/pci/pci.c
> ===================================================================
> --- linux.orig/drivers/pci/pci.c
> +++ linux/drivers/pci/pci.c
> @@ -94,6 +94,9 @@ u8 pci_cache_line_size;
> */
> unsigned int pcibios_max_latency = 255;
>
> +/* If set, the PCIe ARI capability will not be used. */
> +static bool pcie_ari_disabled;


Please update Documentation/kernel-parameters.txt .

--
~Randy
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