[Mesa-stable] [PATCH] swr: MSAA fixes: piglit crashes, additional formats, improve perf.

[Cherniak, Bruce]

Hi Emil,

Thanks for the comments, I’ll work on improving my commit messages.

In this case, the single change to fix crashes yields all 3 improvements  — tests were crashing because our format types were limited.  The additional benefit of supporting these types is much increased performance.  They’re not separable in this case.

Not quite sure of a better/concise way to say that in a one-line, 80 character or less, description.

What will it take to land this fix into stable?  It provides a much better MSAA experience to our customers who are interested in using it.  Having it in the stable release is very desirable.

Thanks,
Bruce

> On Apr 26, 2017, at 8:55 AM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> 
> Hi Bruce,
> 
> On 26 April 2017 at 14:24, Bruce Cherniak <bruce.cherniak at intel.com> wrote:
>> This patch moves msaa resolve down into core/StoreTiles where it can
>> take advantage of all the surface formats - previous resolve
>> was limited to 8-bit unsigned.  This fixes a number of piglit msaa
>> tests that were crashing.  MSAA performance is also greatly improved
>> because resolve is done in parallel.
>> 
>> MSAA is still disabled by default, but can be enabled with
>> "export SWR_MSAA_MAX_COUNT=4" (1,2,4,8,16 are options)
>> The default is 0, which is disabled.
>> 
>> Because it fixes piglit crashes, this should be included in 17.1 stable.
>> 
> As-is this patch will not land in -stable, although regardless the SWR
> team might want to improve their patches - split and commit messages.
> 
> As your commit summary says, you have different things here - crash
> fix, 'new feature" and performance improvement.
> Hence those should be split up in three patches.
> 
> On the topic of commit messages - normally, you do not want to use
> words such as "fix" in the one line summary.
> "fix" describes the result as opposed to what the patch does. Thus if
> you want to know what the patch does you'll have to read it ... only
> to realise that it's not the one you're looking for ;-)
> 
> Some of my favourite articles on the topic of "how/why to write a good
> commit message" are
> 
> http://who-t.blogspot.co.uk/2009/12/on-commit-messages.html
> https://robots.thoughtbot.com/5-useful-tips-for-a-better-commit-message
> 
> Thanks
> Emil