Created attachment 124956 [details]
dmesg-APL-i915.guc_log_level

Created attachment 124957 [details]
i915_guc_info

Created attachment 124958 [details]
i915_guc_load_status

Note that GuC logging is still WIP - see https://patchwork.freedesktop.org/series/7910/

Also the i915_guc_info is showing zero GuC submissions.

I cannot reproduce any issue with guc debugfs output on drm-intel-nightly from 2016-09-15. Note that valid values for parameter i915.guc_log_level are -1,0,1,2,3. Using guc_log_level=1, I can see output from i915_guc_log_dump immediately after boot. Also i915_guc_load_status and i915_guc_info report valid values.

Is this still an issue? I suspect that these GuC interfaces were just not understood.

I see no logs in guc_log_dump as well. The i915_guc_info reports 0 submissions and 0 failures and the guc_log_dump is empty. The value of parameter thatI have given is i915.guc_log_dump=1.

Even when i915_guc_info reports positive number of submissions, the guc_log is empty.

"The value of parameter thatI have given is i915.guc_log_dump=1."

This is not the correct parameter. The parameter for guc log verbosity control is i915.guc_log_level. Valid values are -1,0,1,2,3.

I see log content immediately after boot with i915.guc_log_level=1. Note that GuC submission *must* be enabled for logging to be enabled. GuC loading alone is not enough.

Also please cat the i915.guc_log_level after boot. There may be conditions where driver will override the value back to -1 (disabled).

Also please clarify "guc_log is empty". Do you see no output when you read, or do you see output with mostly 0x00000000 entries? If the later, you may have to scan down to find actual logged codes. Each 4K page of the logging buffer is designated for different purpose.

I confirm guc debugfs output works. I checked with i915.guc_log_level=2.

Platform BXT-P: APL system
CPU Name : Intel(R) Genuine Processor @ 1.1 GHz (family: 6, model: 12, stepping: 9) 4 cores
QDF : Q6HE
SoC : B1
CRB : Apollo Lake DDR3L RVP1A FAB2
Reworks: R19, R20

Software 
Bios: 144_B10 APLK_B0_IFWI_X64_R_2016_06_27_0956_SPI_RVP1.bin from \\gar\ec\proj\ba\CCG\APL BIOS\External\BIOS_Release\Daily\v144_10_2016_WW27.1\IFWI\IFWI_RVP1_Release\IFWI
KSC: 1.15
Linux distribution: Ubuntu 16.04 64 bits
DMC 1.07
GuC 8.7
Kernel: 4.8.0 f35ed31 from http://cgit.freedesktop.org/drm-intel/
  commit f35ed31aea66b3230c366fcba5f3456ae2cb956e
  Author: Jani Nikula <jani.nikula@intel.com>
  Date:   Mon Oct 10 14:29:09 2016 +0300
  drm-intel-nightly: 2016y-10m-10d-11h-28m-51s UTC integration manifest
libdrm-2.4.71 a44c9c3 from git://anongit.freedesktop.org/mesa/drm
mesa: mesa-12.0.0 8b06176 from git://anongit.freedesktop.org/mesa/mesa
cairo 1.15.2 db8a7f1 from git://anongit.freedesktop.org/cairo
xorg-server-1.18.99.901-76 97a8353 from git://git.freedesktop.org/git/xorg/xserver
xf86-video-intel 2.99.917-712 696f58f from git://git.freedesktop.org/git/xorg/driver/xf86-video-intel
libva-1.7.2-38 3b7e499 from git://git.freedesktop.org/git/vaapi/libva 
vaapi-intel-driver: 1.7.2-133 dd73514 from git://git.freedesktop.org/git/vaapi/intel-driver
External screens: ASUS PB238Q (HDMI), LG 25UM55D (DP)

So closed