On 12/8/05, Alan Cox <[EMAIL PROTECTED]> wrote: > On Iau, 2005-12-08 at 19:52 +0800, Austin Yuan wrote: > > buffer. Because the interface of "alloc_by_type" only receives a > > simple parameter "type", here I hide the user space address into > > "type" and re-get it in alloc_userspace_memory. > > That should probably be fixed by extending the API to pass both > > > I use this interface to easily implement XAA readpixmap/imagewrite > > driver interfaces, and get a better performance. Here, I didn't attach > > the patch for i810 driver. I just want to get some comments about it, > > and if you think it makes sense, I'd like to make it more generic. > > > > Any comments are appreciated, thanks. > > > The one thing I don't understand looking at this is that I understood > AGP pages should be marked uncached. However user space pages may exist > in many mappings and the CPU also requires all mappings of a page are > consistent. > > Does i8xx need the page uncached or is it enough to wbinvd the pages in > question on writing and invalidate them before reading, or does the i8xx > in fact take full part in the cache coherency ?
I read through the spec, and just get a rough concept and don't understand very well about it. The mapping of gart memory has two types, one is non-snooped, and another is snooped. Intel Linux gart driver only uses non-snooped type, and the meaning is that physical address backing the gart targets non-snooped main memory. My experiment uses this type. For snooped memory, it targets cacheable main memory (cause snoop on processor bus). I haven't understood the explanation about it. It says this type memory must not be targeted by the processor through graphics memory range, and such accesses will not be snooped after translation. And accesses via instruction stream are permitted, yet treated as unsnooped main memory. This removes restrictions regarding instruction stream overfetches into dissimilar graphics memory region. > > _______________________________________________ > xorg mailing list > [EMAIL PROTECTED] > http://lists.freedesktop.org/mailman/listinfo/xorg > ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_idv37&alloc_id865&op=click -- _______________________________________________ Dri-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dri-devel
