cbd2d08c74
[Problem description] 1. Boot up picasso platform, launches desktop, Don't do anything (APU enter into "gfxoff" state) 2. Remote login to platform using SSH, then type the command line: sudo su -c "echo manual > /sys/class/drm/card0/device/power_dpm_force_performance_level" sudo su -c "echo 2 > /sys/class/drm/card0/device/pp_dpm_sclk" (fix SCLK to 1400MHz) 3. Move the mouse around in Window 4. Phenomenon : The screen frozen Tester will switch sclk level during glmark2 run time. APU will enter "gfxoff" state intermittently during glmark2 run time. The system got hanged if fix GFXCLK to 1400MHz when APU is in "gfxoff" state. [Debug] 1. Fix SCLK to X MHz 1400: screen frozen, screen black, then OS will reboot. 1300: screen frozen. 1200: screen frozen, screen black. 1100: screen frozen, screen black, then OS will reboot. 1000: screen frozen, screen black. 900: screen frozen, screen black, then OS will reboot. 800: Situation Nomal, issue disappear. 700: Situation Nomal, issue disappear. 2. SBIOS setting: AMD CBS --> SMU Debug Options -->SMU Debug --> "GFX DLDO Psm Margin Control": 50 : Situation Nomal, issue disappear. 45 : Situation Nomal, issue disappear. 40 : Situation Nomal, issue disappear. 35 : Situation Nomal, issue disappear. 30 : screen black. 25 : screen frozen, then blurred screen. 20 : screen frozen. 15 : screen black. 10 : screen frozen. 5 : screen frozen, then blurred screen. 3. Disable GFXOFF feature Situation Nomal, issue disappear. [Why] Through a period of time debugging with Sys Eng team and SMU team, Sys Eng team said this is voltage/frequency marginal issue not a F/W or H/W bug. This experiment proves that default targetPsm [for f=1400MHz] is not sufficient when GFXOFF is enabled on Picasso. SMU team think it is an odd test conditions to force sclk="1400MHz" when GPU is in "gfxoff" state，then wake up the GFX. SCLK should be in the "lowest frequency" when gfxoff. [How] Disable gfxoff when setting manual mode. Enable gfxoff when setting other mode(exiting manual mode) again. By the way, from the user point of view, now that user switch to manual mode and force SCLK Frequency, he don't want SCLK be controlled by workload.It becomes meaningless to "switch to manual mode" if APU enter "gfxoff" due to lack of workload at this point. Tips: Same issue observed on Raven. Signed-off-by: chen gong <curry.gong@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.