Re: [PATCH v5 7/7] Documentation: ABI: Add CXL PCI cxl_reset sysfs attribute

[Alex Williamson]

On Fri, 6 Mar 2026 09:23:22 +0000
<smadhavan@xxxxxxxxxx> wrote:

> From: Srirangan Madhavan <smadhavan@xxxxxxxxxx>
> 
> Document the cxl_reset sysfs attribute added to PCI devices that
> support CXL Reset.
> 
> Signed-off-by: Srirangan Madhavan <smadhavan@xxxxxxxxxx>
> ---
>  Documentation/ABI/testing/sysfs-bus-pci | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
> index b767db2c52cb..d67c733626b8 100644
> --- a/Documentation/ABI/testing/sysfs-bus-pci
> +++ b/Documentation/ABI/testing/sysfs-bus-pci
> @@ -174,6 +174,28 @@ Description:
>  		similiar to writing 1 to their individual "reset" file, so use
>  		with caution.
> 
> +What:		/sys/bus/pci/devices/.../cxl_reset
> +Date:		February 2026
> +Contact:	linux-cxl@xxxxxxxxxxxxxxx
> +Description:
> +		This attribute is only visible when the device advertises
> +		CXL Reset Capable in the CXL DVSEC Capability register
> +		(CXL r3.2, section 8.1.3).
> +
> +		Writing 1 to this file triggers a CXL device reset which
> +		affects CXL.cache and CXL.mem state on all CXL functions
> +		(i.e. those not listed in the Non-CXL Function Map DVSEC,
> +		section 8.1.4), not just CXL.io/PCIe state.  This is
> +		separate from the standard PCI reset interface because CXL
> +		Reset has different scope.
> +
> +		The reset will fail with -EBUSY if any CXL regions using this
> +		device have drivers bound.  Active regions are torn down as
> +		part of the reset sequence.

There's no such test afaict.  Thanks,

Alex

> +
> +		This attribute is registered by the CXL core when a CXL device
> +		is discovered, independent of which driver binds the PCI device.
> +
>  What:		/sys/bus/pci/devices/.../vpd
>  Date:		February 2008
>  Contact:	Ben Hutchings <bwh@xxxxxxxxxx>
> --
> 2.43.0
> 
>