https://bugs.freedesktop.org/show_bug.cgi?id=39202 --- Comment #33 from Ilija Hadzic <ihadzic@xxxxxxxxxxxxxxxxxxxxxx> 2011-08-18 08:50:00 PDT --- (In reply to comment #32) > I can connect only the VGA connector as I have only one LCD monitor without DVI > or HDMI slots. The video card has VGA, HDMI and DVI connectors. If you have some spare change in your pocket you can get some HDMI-to-VGA and DVI-to-VGA converter dongles to try out (they are no more than 5-10 bucks a pop) and trying out different connectors might give us some good datapoints. > Maybe the old kernel is broken even on VGA (crtc1) (the patch says crtc>1 and > not crtc>=1)? No. crtc>1 is correct message associated with the patch, but the user space also plays the role here. Specifically the old kernel could only distinguish between primary and secondary crtc and treated primary as 0 and secondary as 1. User space on the other hand could at its own discretion map the real crtc number to primary or secondary. Prior to the patch, radeon DDX called 0 primary and everything else secondary so all crtcs >=1 mapped to 1, but 1 was correctly mapped. Fixed radeon DDX maps all crtcs correctly, but it refuses to use vblank synchronization with old kernel. New kernel on the other hand still understands and accepts primary/secondary notation for backward compatibility with old DDX, but with the understanding that it may wait on wrong CRTC if user space is old. How KDE (assuming that it calls the vblank ioctl directly) determines the CRTC number is anyone's guess but if it does similar primary/secondary mapping of high crtcs like DDX did, things will look strange. We need to find that out, so can you please check which CRTC does the glxgears use in your case and which CRTC does the KDE use? You can do that by enabling debug in drm (echo 7 > /sys/module/drm/parameters/debug) and searching the kernel log for "waiting on vblank count %d, crtc %d\n" string that comes from drm_wait_vblank function in drm_irq.c. Make sure that you use the kernel *with* the crtc>1 patch because the one without will not properly handle high crtcs. Beware that the log will be very verbose once you turn the debug on. If you are overwhelmed by other messages you could temporary change the relevant DRM_DEBUG statement in drm_irq.c into DRM_INFO and recompile the kernel; then you won't have to turn on the debug parameter. Observe the log and try to figure out which CRTCs are used by whom. If it turns out that the one from KDE is different from the one from glxgears, then we need to figure out which one is wrong and why (in that case the problem will point to userland). BTW, I may have mispoken in my previous post. Looking back at my logs it's the VGA that typically sits on CRTC2 and DVI is CRTC1, so by using the VGA port you may very easily be sitting on a CRTC number that is mishandled in older kernels. On the other hand CRTCs are dynamically routed to connectors and if you have only one connector hooked up to the monitor, the driver *should* in most cases route everything to CRTC0, but that part of the code is quite complex and it is not excluded that you indeed end up on CRTC2. We'll see that after you do the experiment I described. -- Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
