The previous detection was based on color depth only to determine the
texture format to use in GLX. If that worked fine at depths 24 (RGB8)
and 32 (ARGB8), that would fail at depth 30 (BGR10) and fallback to
software instead of using the TFP extension.
This commit uses an efficient population count implementation to
compare the number of 1-bits in color masks against the color depth
requested by the X client. If they are not equal this means that an
alpha channel has been requested.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
895055c836