[prev in list] [next in list] [prev in thread] [next in thread] 

List:       linux-acpi
Subject:    Re: [PATCH 1/2] acpi: bgrt: Fix the way the BGRT status field is used.
From:       Josh Triplett <josh () joshtriplett ! org>
Date:       2019-01-30 0:56:48
Message-ID: 20190130005648.GA3558 () localhost
[Download RAW message or body]

On Tue, Jan 29, 2019 at 09:10:08PM +0100, Môshe van der Sterre wrote:
> Hi Peter,
> 
> On 01/29/2019 07:51 PM, Peter Jones wrote:
> > The BGRT table's "status" field doesn't indicate "validity", but rather
> > if and how the image is being displayed.  As such, we shouldn't decide
> > the table is invalid if status bits we don't understand are in use, and
> > it's better to expose the values we do understand directly.
> 
> This goes against the conclusion of this discussion from 2015:
> https://patchwork.kernel.org/patch/6688521/
> I wasn't involved with that discussion, so I have CC-ed the participants.

Reading this patch: please don't remove the check entirely, please just
check for flags set that the implementation doesn't understand (which
now would be & 0xf8 instead of & 0xfe).

We have no way of knowing whether another field added in the reserved
bits could change the interpretation of the image.

- Josh Triplett
[prev in list] [next in list] [prev in thread] [next in thread]