On 2021/8/5 7:52, Bjorn Helgaas wrote:

On Wed, Aug 04, 2021 at 09:47:06PM +0800, Dongdong Liu wrote:

quoted

PCIe spec 5.0 r1.0 section 2.2.6.2 says that if an Endpoint supports
sending Requests to other Endpoints (as opposed to host memory), the
Endpoint must not send 10-Bit Tag Requests to another given Endpoint
unless an implementation-specific mechanism determines that the Endpoint
supports 10-Bit Tag Completer capability. Add a 10bit_tag sysfs file,
write 0 to disable 10-Bit Tag Requester when the driver does not bind
the device if the peer device does not support the 10-Bit Tag Completer.
This will make P2P traffic safe. the 10bit_tag file content indicate
current 10-Bit Tag Requester Enable status.

Signed-off-by: Dongdong Liu <redacted>

quoted

+		The file is also writeable, the value only accept by write 0
+		to disable 10-Bit Tag Requester when the driver does not bind
+		the deivce. The typical use case is for p2pdma when the peer
+		device does not support 10-BIT Tag Completer.

s/10-BIT/10-Bit/

Will fix and will check other place.

Thank,
Dongdong

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