https://bugzilla.kernel.org/show_bug.cgi?id=28932
Summary: new avivo PLL calculation in Radeon driver fails with certain modelines Product: Drivers Version: 2.5 Kernel Version: 2.6.38-rc4 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) AssignedTo: drivers_video-dri@kernel-bugs.osdl.org ReportedBy: bitbytebit@gmail.com Regression: Yes
This patch https://bugs.freedesktop.org/attachment.cgi?id=41943 fails to calculate the PLL values for certain lower dotclock modelines. I can change the code to use the legacy PLL calculation and things work again.
Here's an example modeline that fails now, used to work flawless...
# mario 256x224@59.19 15.2699Khz ModeLine "256x224x59.19" 5.130681 256 272 296 336 224 233 236 258 -HSync -VSync
This modeline now with the newer avivo PLL calculation ends up being 133Hz instead of 59.19 and the Horizontal frequency is 39khz or so. It's basically completely wrong, way off of what it should be.
Things work fine for anything that seems to have a dotclock above 12 Mhz or so, from what I suspect the newer method isn't taking into account possible lower dotclock and Horizontal frequency modelines.
Thanks, Chris