| Summary: | miniDP to external monitor with DVI-D via miniDP to HDMI/DVI-D/DP adapter : DP dual mode HDMI ID: (err -6) and blank screen | ||||||||||||||||
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| Product: | DRI | Reporter: | genpur | ||||||||||||||
| Component: | DRM/Intel | Assignee: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||||||||||||
| Status: | CLOSED WORKSFORME | QA Contact: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||||||||||||
| Severity: | normal | ||||||||||||||||
| Priority: | medium | CC: | genpur, intel-gfx-bugs | ||||||||||||||
| Version: | XOrg git | ||||||||||||||||
| Hardware: | x86-64 (AMD64) | ||||||||||||||||
| OS: | Linux (All) | ||||||||||||||||
| Whiteboard: | |||||||||||||||||
| i915 platform: | SNB | i915 features: | display/DP | ||||||||||||||
| Attachments: |
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Description
genpur
2018-04-04 21:23:36 UTC
Created attachment 138604 [details]
dmesg_kernel-4.13.0-38-generic.log
Created attachment 138605 [details]
EDID of monitor iiyama ProLite E1900S
Created attachment 138606 [details]
EDID of TV Panasonic
Not sure I managed to parse the underlying problem correctly. Is is that the EDID read fails with the troublesome monitor+dongle combination? Please boot with the troublesome monitor+dongle combination without any extra parameters on the kernel cmdline except drm.debug=0xe. Created attachment 138625 [details]
dmesg_Problematical_monitor.log
Created attachment 138626 [details] dmesg_Non-problematical_PanasonicTV.log "Is that the EDID read fails with the troublesome monitor+dongle combination?" I don't know what is the real cause that problematical monitor is not activated. This is my main problem. First idea was to connect other device to dongle instead of problematical monitor, so I connected TV. TV has been detected without any problem, display was active, everything was working. Later on, I have found on internet that when people trying to connect some monitors (esspecially via KVM switch or some video adapters) there can be a problem with reading EDID from connected display. So, I ASSUMED that this can be the reason... To avoid situation that my laptop (because of any reason) can't read EDID properly, I decided to try putting EDID directly (into kernel parameters on boot stage in grub2 or put into initram image). I have expected that in this case my integrated Intel grapics card should force output of miniDP port to desired parameters, like "video=HDMI-A-1:1280x1024-16@75D drm.edid_firmware=HDMI-A-1:edid/monitor.bin". Result was the same - blank monitor - but parameters /sys/class/drm/card1-HDMI-A-1/{modes,enabled,status,edid} where correct. My conclusion was that EDID has been read "locally" from initram image properly, but it's not enough to activate problematic monitor. Then I have compared log files of problematical monitor and non-problematical TV. I saw that only difference is here : [drm:drm_dp_dual_mode_detect [drm_kms_helper]] a) when display was activated DP dual mode HDMI ID: DP-HDMI ADAPTOR\004 (err 0) b) when display was not activated DP dual mode HDMI ID: (err -6) I know generally there can be a possibility that EDID is corrupted. But if this will be the case, this problematical monitor should not work with other computer (in my opinion only). But it works. So I focus on err=-6 right now and ask experts like you for help. I have attached 2 log files (both are dmesg with drm.debug=0xe extra kernel parameter only) attachment 1 [details] [review]: Dongle + Problematical monitor combination attachment 2 [details] [review]: Dongle + Non-problematical TV combination Somehow the entire dongle seems to disappear when you plug it into the bad monitor. That's causing the drm_dp_dual_mode_detect() difference. Also it seems to affect the DP AUX channel somehow as the timeouts that I would expect to see are no longer there. So my theory is that somehow the dongle does not detect your bad monitor and defaults into some kind of DP passthrough mode instead. The dongle has a DP output also right? That could perhaps explain why nothing is detected, and also why no picture goes through when you override the EDID. Did you try different cables between the dongle and the display? Also trying both the DVI and HDMI oputputs of the dongle is worth a shot. And if the monitor has multiple DVI/HDMI inputs you should also try all of them. If none of that helps then I'm afraid it looks like you need to either get another dongle, or another display. Reporter, can you answer this question made by Ville? Next days I will try with other dongle. I will give a feedback. Closing, please re-open if occurs again. |
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