| Summary: | [BSW Bisected] eDP screen is blank when external HDMI monitor is connected | ||||||
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| Product: | DRI | Reporter: | Jeff Zheng <jeff.zheng> | ||||
| Component: | DRM/Intel | Assignee: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||
| Status: | CLOSED FIXED | QA Contact: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||
| Severity: | critical | ||||||
| Priority: | high | CC: | intel-gfx-bugs, vandana.kannan | ||||
| Version: | unspecified | ||||||
| Hardware: | Other | ||||||
| OS: | All | ||||||
| Whiteboard: | |||||||
| i915 platform: | i915 features: | ||||||
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There are two extra issues 1. When running "testdisplay -a/d", HDMI screen will flash for some resolutions. 2. If booting BSW without HDMI, eDP screen shows text. But "testdisplay -a/d" will make eDP screen black and unable to recover. I'm not sure whether or not above two issues has same root cause of this bug. If any one is a new issue, please let me know and I will report regression bug. Bisected and below is the bisect info: 371abae844ede392066bfc21202b2e40f4a654d1 is the first bad commit commit 371abae844ede392066bfc21202b2e40f4a654d1 Author: Deepak M <m.deepak@intel.com> Date: Mon Dec 15 15:58:21 2014 +0530 drm/i915: Parsing LFP brightness control from VBT From the logs, printed by the bad commit: [ 2.287394] [drm:parse_lfp_backlight] BL control pin is not DDI (pin 0) Seems to me either the VBT version check is wrong or the VBT in the devices is busted. To enable BLC, VBT version >= 191 needs to have control pin set to 2 (DDI PWM). This is because only PWM via DDI has been enabled as of now. This check has to be changed when support for any of the other control pins would be added. (In reply to Vandana Kannan from comment #4) > To enable BLC, VBT version >= 191 needs to have control pin set to 2 (DDI > PWM). This is because only PWM via DDI has been enabled as of now. > This check has to be changed when support for any of the other control pins > would be added. So you're saying the VBT spec was changed, but the VBT on these platforms does not conform to the spec? Tried on latest -nightly commit cbb440bf6e71044410db1645991fe89b3f57894f with BIOS version 0.51.3 and still saw this issue. commit 9025452366e9a86f2e11292865d98430341005d1 Author: Rodrigo Vivi <rodrigo.vivi@intel.com> Date: Tue Jan 6 14:48:15 2015 -0500 Revert "drm/i915: Parsing LFP brightness control from VBT" Verified on 2015_01_08 commit 296cb88821b7113a9add839ba1e8e116ff13ecc0. Both HDMI and eDP screens show text. Closing old verified. |
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Created attachment 111262 [details] dmesg ==System Environment== -------------------------- BIOS version 0.49 Regression: Yes. I tried -next-queued 2014_12_05 commit 8f4d2683b02ad8059bf1861acef64c022b9d5ce6 and both eDP and HDMI screens show text. Non-working platforms: BSW ==kernel== -------------------------- -queued: 2014_12_24 commit 140fd38dc4962ae3694f81900b51c567df1b6d33(test fails) ==Bug detailed description== ----------------------------- eDP screen is blank when HDMI monitor is connected. Boot BSW with HDMI monitor (HP 2309P)connected, when login appears on HDMI screen, the eDP screen does not show anything. ==Reproduce steps== ---------------------------- 1. Connect HDMI monitor to BSW and boot BSW 2. When login appears on HDMI screen, the eDP screen does not show anything 3. Running xinit shows xterm on HDMI display, but eDP screen still does not show anything.