On Sun, 7 Sep 2008 21:34:52 +0000 "Leonti Bielski" <[EMAIL PROTECTED]> babbled:
> Hello! > Somewhere I read that Qtopia is much faster than other distros because > it uses framebuffer. So I have some questions: misnoma. wrong. > 1. How is it possible for qtopia to bypass glamo chip and write > directly to the framebuffer? fb is available - but you will be competing with x for the fb and so you can choose - either qtopia and all - or x. not both. you can use x to write to the fb - it is simply an organised way of doing so. (ie you write to an shm buffer then xshmputimage the regions u want). > 2. Is it possible to do the same with x11 server? > 3. Is there other explanation(except for glamo) why apps are slow to > respond on 400mhz proc? "bandwidth" to glamo - it holds the cpu in waitstates while writing to video ram (the framebuffer) so all time spent writing is lost as cycles to do anything else. and it's pretty slow (7mb/sec). for example. lets say i spend 1 second to write data to video ram - that is 1 second i CANNOT spend on anything else. the glamo limits write rates to about 7mb/sec (so the memcpy() to video ram is artificially slowed down compared to what it would be mem -> mem which would be about 50mb/sec so you lose about 85% of your cpu cycles entirely while writing to video ram). the glamo has acceleration - not everything, but a reasonable set (not really any less than most desktop x drivers when it comes to 2d). > Thank you! > > _______________________________________________ > Openmoko community mailing list > [email protected] > http://lists.openmoko.org/mailman/listinfo/community > -- ------------- Codito, ergo sum - "I code, therefore I am" -------------- The Rasterman (Carsten Haitzler) [EMAIL PROTECTED] _______________________________________________ Openmoko community mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/community
