Am 24.01.2011 20:13, schrieb Chris Wilson: > On Mon, 24 Jan 2011 19:48:55 +0100, Knut Petersen wrote: > >> On an AOpen i915GMm-HFS I see the following problem: >> The LCD panel connected to DVI-1 gets disabled and then reenabled >> under high system load (e.g. -j 15 kernel compile) if I am working on the >> framebuffer console (no problems in X). >> > DVI detection is essentially retrieving the EDID by bitbanging on the DDC. > This is timing sensitive and I suspect that is being interrupted by the > system activity causing the EDID data to be returned corrupted. Is that > supported by any warnings in dmesg? Does increasing the drm.debug level to > 0x6 reveal any more significant information? > > KERNEL 2.6.36.3 ============== Attached to this msg is LOG 2.6.36.3. Everything looks fine, every 10 seconds an additional message group is added. No distortions. KERNEL 2.6.38-rc2 ================ LOG-2.6.38-rc2 is different. The kernel is a pure kernel 2.6.38-rc2 with one exception: I changed DRM_OUTPUT_POLL_PERIOD to 3*HZ to increase error probability. At log time [ 678.598641] you can see the status change of the VGA-2 connector (there is no physical VGA-2 connector on that mobo). After that a hotplug event is generated. Ok, that could be reasonable, but as you see the other connectors are also affected by that event. I cannot tell the exact moment, but during processing that hotplug event there is a period with no (or maybe a distorted) signal on the DVI-1 connector. Both logs where taken on a busy system doing a make -j 15 kernel compile, debuglevel 15, framebuffer console, no X running. I admit that I had not the time to study the code and hardware references in detail, but a few questions / thoughts come to my mind. 1: I suspect that it is not a timing problem because only VGA-2 (no physical connector) is affected. The status of VGA-1 and DVI-1 (with physical connectors) seems to be absolutely stable. Guess: Maybe a hardware problem like missing termination ? There are few systems with 2 real VGA connectors ... there could be more systems with that problem if my guess is right. 2: We should not care if connector status changes between "unknown" and "disconnected". We should only care about status changes from/to "connected" and generate hotplug events only in that case. That should solve my problem and would break nothing. Am I right? 3: It's wrong that a status change on one connector generates a hotplug event that affects all connectors ... I think LOG-2.6.38-rc2 shows a sign of an additional bug =========================================== [ 681.527815] [drm:drm_target_preferred], found mode 1280x1024 [ 681.531482] [drm:drm_setup_crtcs], picking CRTCs for 4096x4096 config Is 4096x4096 really reasonable? I don't think so, at least not for my hardware. After connecting a monitor to both the DVI and VGA connectors it can use xrandr to set different viewing areas for the monitors. But although X also reports that maximum 4096x4096 screen size it is not usable. X will crash as soon as I try to use a combined x-resolution above 2048. I remember that I read somewhere that this is a hardware limit of my hardware. Is X taking the maximum screen resolution from the kernel? I think so. So the kernel should not use a screen config that is beyond hardware limits. lspci: 00:00.0 Host bridge: Intel Corporation Mobile 915GM/PM/GMS/910GML Express Processor to DRAM Controller (rev 04) 00:02.0 VGA compatible controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 04) 00:02.1 Display controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 04) 00:1b.0 Audio device: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) High Definition Audio Controller (rev 04) 00:1c.0 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 1 (rev 04) 00:1c.1 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 2 (rev 04) 00:1c.2 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 3 (rev 04) 00:1c.3 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 4 (rev 04) 00:1d.0 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #1 (rev 04) 00:1d.1 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #2 (rev 04) 00:1d.2 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #3 (rev 04) 00:1d.3 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #4 (rev 04) 00:1d.7 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB2 EHCI Controller (rev 04) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev d4) 00:1f.0 ISA bridge: Intel Corporation 82801FBM (ICH6M) LPC Interface Bridge (rev 04) 00:1f.1 IDE interface: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) IDE Controller (rev 04) 00:1f.2 IDE interface: Intel Corporation 82801FBM (ICH6M) SATA Controller (rev 04) 00:1f.3 SMBus: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) SMBus Controller (rev 04) 02:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8053 PCI-E Gigabit Ethernet Controller (rev 19) 03:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8053 PCI-E Gigabit Ethernet Controller (rev 19) 05:03.0 FireWire (IEEE 1394): Agere Systems FW322/323 (rev 61) Knut