On Wed, 4 May 2005, paul womack wrote: > David Dawes wrote: > > On Tue, May 03, 2005 at 12:53:43PM -0700, Mark Vojkovich wrote: > > > >> This stuff is HW specific so it needs to be done by the driver. > >>Looking through the i810 driver source code, it appears the i810 > >>driver supports gamma but the i830 driver does not. I don't know > >>the reason behind that. Perhaps David Dawes knows. I see he's > >>worked on the i830 driver. > > > > > > I no longer have access to the relevant documentation, and don't recall > > if was omitted because of hardware limitations or other reasons. Someone > > with access to the hardware specs should be able to provide a better answer > > to this. > > OK. Assuming that some cards don't have HW support for gamma > correction, that leaves owners of those cards with uncontrollable > displays. I would be very surprised if any modern graphics card did not support gamma correction. > > I suppose I can split my question into 2; my real request > is (of course) for wonderful accurate screen display. > > 1) Can gamma correction be added/incorporated into the driver? If somebody has appropriate documentation for that chip, yes. It's probably just a matter of passing the CMAP_PALETTED_TRUECOLOR flag to xf86HandleColormaps and setting some magic bit in the hardware somewhere. Mark. > 2) If the answer to (1) is no (for whatever reason) is it possible > (even if undesirable) to gamma compensate the data being sent > to the driver; it is clear that this approach will suffer from > range and quantisation issues, but it can't be (much) worse > than what I have at the moment, which is (judging by screen cards) > a non-negotiable gamma of 1.6, against a desired 2.2 > > Perhaps some kind of driver "decorator" ? > > http://www.exciton.cs.rice.edu/JavaResources/DesignPatterns/DecoratorPattern.htm > > BugBear > _______________________________________________ > XFree86 mailing list > XFree86@xxxxxxxxxxx > http://XFree86.Org/mailman/listinfo/xfree86 > _______________________________________________ XFree86 mailing list XFree86@xxxxxxxxxxx http://XFree86.Org/mailman/listinfo/xfree86
