RE: [PATCH] RapidIO: Fix use of non-compatible registers

Andrew Morton [off-list ref] wrote:

On Tue, 26 Jul 2011 14:07:26 -0400
Alexandre Bounine [off-list ref] wrote:
=20

quoted

Replace/remove use of RIO v.1.2 registers/bits that are not forward-

compatible

quoted

with newer versions of RapidIO specification.

RapidIO specification v. 1.3 removed Write Port CSR, Doorbell CSR,
Mailbox CSR and Mailbox and Doorbell bits of the PEF CAR.

.....

You did a cc:stable but provided no reason (that I can understand) for
backporting the patch.  Please explain why the problem is sufficiently
serious to warrant this action.

My reason for this is that use of removed (since RIO v.1.3) register
bits
affects users of currently available 1.3 and 2.x compliant devices who
may
use not so recent kernel versions.

Removing checks for unsupported bits makes corresponding routines
compatible
with all versions of RapidIO specification. Therefore, backporting makes
stable
kernel versions compliant with RIO v.1.3 and later as well.=20