0000:00:14.0 VGA compatible controller: S3 Inc. 86c325 [ViRGE] (rev 02) Not an XAA problem (still broken under noaccel), nor is it fixed by any of the timing options for the virge driver. VESA works though. easiest way to reproduce this is to run x11perf on a fresh server. the noise pixels are always white, and seem to be offset down and right about 64 pixels from the window being drawn. they appear to be transient, ie when nothing's being drawn the display is correct. i'll test with the xf4.[0123] releases.
under further experimentation, this _is_ a timing problem. the default memclk was something like 53.884MHz, cranking it to 60MHz eliminates the noise. underclocking memory actually made the pixel noise worse.
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.