Re: [PATCH v1 1/2] PCI: ATS: Add function to check ATS page aligned request status.

From: Sinan Kaya
Date: Mon Feb 11 2019 - 15:35:19 EST

On 2/11/2019 2:15 PM, Raj, Ashok wrote:
It seems rather odd we have to check for ATS version.

I always assumed unspecified bits (Reserved) must be 0. We only check
this if ATS is enabled, and this particular bit wasn't given away for another

Is it really required to check for ATS version before consuming this?

Reading again, it looks like version check is not necessary since it
is implied by the presence of this bit per this paragraph.

Page Aligned Request â If Set, indicates the Untranslated Address is always aligned to a 4096 byte boundary. Setting this bit is recommended. This bit permits software to distinguish between implementations compatible with earlier version of this specification that permitted a requester to supply anything in bits [11:2].