> DCE4 parts (like the 5570) only have an external clock if the OEM supplied > it, hence not all boards have it. Also, the external clock source can only > be used to drive native DP (DisplayPort), not non-DP outputs like DVI or HDMI > or VGA or a passive DP to DVI/HDMI convertor. If you are using 3 non-DP > displays, that will only work if at least two of the displays have the exact > same clock and hence can share a PLL. If you want to use a the external > clock, the board has to have it, and if it does, it can only be used for DP. > There are lots of other complex cases and limitations as well depending on > the asic. Thanks Alex. Yes, I know. The DisplayPort actually goes through an Accell "UltraAV DisplayPort 1.2 to HDMI 1.4 active adapter". But I do not know if the board actually has the external clock source installed. Is this external clock probed by the driver? Is there a log message about the existence or nonexistence of the "external clock"? The radeon driver does not seem to report any detail about what it has found in the hardware, and so, it is very difficult to infer what "should" or "should not" be possible with the display configurations. Actually, with Xorg and Weston, it seems I have to force _all_three_ interfaces to the same clock, even though, presumably, there are at least two separate PLLs. Can the DisplayPort _not_ use the - possibly "random" - clock from the other display interfaces? Does the DisplayPort have to have an _independent_ clock source? Subsequently, using xrandr, I can try to force, for instance, DVI-0 to a different clock, but it does nothing. "xrandr --verbose" will report the new mode, but the log shows an error, kernel: [drm:atombios_crtc_mode_fixup [radeon]] *ERROR* unable to allocate a PPLL FIVE kernel: [drm:drm_crtc_helper_set_config [drm_kms_helper]] *ERROR* failed to set mode on [CRTC:32] and the display menu reports that the display is still running in the old mode. That is a mess with xrandr, since what it is reporting is then wrong. Also, running three displays on a Virtual Terminal is a mess, with one display showing the Virtual Terminal in a "least common denominator" mode for all three displays, and with the other two displays still showing the previous Xorg display. For the moment, it would be most useful if the radeon driver would disclose the specific hardware configuration it was "seeing", for instance, the exact number of "working" clock sources, and the exact number of crtc's, and to also disclose how the clock sources were being deployed, for instance, specifically, which clock sources were being shared, and which were being made "exclusive". James _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
