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

[Randy Dunlap <rdunlap@xenotime.net>]

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

> From: Rafael J. Wysocki <rjw@sisk.pl>
> 
> 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@sisk.pl>
> ---
>  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