Subject: bug#10397: [PATCH] Under Remote Desktop, NUMCOLORS is unreliable; workaround

From: Daniel Colascione <[email-masked]>
Date: Thu, 29 Dec 2011 08:42:37 -0800

On 12/29/11 8:27 AM, Juanma Barranquero wrote:
> On Thu, Dec 29, 2011 at 17:23, Daniel Colascione <[email-masked]> wrote:
> 
>> Why? What's the point of adding the extra complexity?
>> Setting cap to -1 leads to this line
>>
>>    1 << min (dpyinfo->n_planes * dpyinfo->n_cbits, 24);
>>
>> which produces a reasonable result for direct color displays.
>> Why keep using NUMCOLORS, which we know to be broken?
> 
> No, you said that NUMCOLORS is known to be broken in a very specific
> case. In the general, non-RemoteDektop case, it works. 

I'm not convinced there aren't other bugs lurking in the code backing
NUMCOLORS; after all, it's doing the same simple calculation we are, and
it's somehow doing it wrong.

http://msdn.microsoft.com/en-us/library/dd144877%28v=VS.85%29.aspx#3
suggests that NUMCOLORS is generally flaky.

> Can you
> guarantee that for every non-palettized display, it will produce the
> same number? Because otherwise you're changing the current behavior
> for people who's not affected by the RemoteDeskopt-related bug.

No, I can't guarantee that my original change always produces the same
results: it might fix other bugs.