[Bug 98897] New: Macbook pro 11,5 screen flicker when AC adapter plugged in

bugzilla-daemon at freedesktop.org bugzilla-daemon at freedesktop.org
Tue Nov 29 09:50:38 UTC 2016


            Bug ID: 98897
           Summary: Macbook pro 11,5 screen flicker when AC adapter
                    plugged in
           Product: xorg
           Version: unspecified
          Hardware: x86-64 (AMD64)
                OS: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: Driver/Radeon
          Assignee: xorg-driver-ati at lists.x.org
          Reporter: tom at r.je
        QA Contact: xorg-team at lists.x.org

I originally posted this at kernel.org
https://bugzilla.kernel.org/show_bug.cgi?id=189231 but was instructed to post
it here.

As of recent kernels (Sorry I don't have the exact number but at least 4.8.8)
there is problem with the screen flickering on a Macbook Pro 11,5.

There's an ongoing discussion here:

Machine specs:

Macbook Pro 11,5 (Retina)
Intel i7 4870HQ
Radeon  M370X (radeon graphics driver, amdgpu does not seem to be supported so
I couldn't see if its' a gpu driver issue)

I can record a video using a camera if it would be useful, but it looks like
graphical corruption, it looks like windows are being drawn at the wrong XY
coordinates on some frames, this is made worse when a window is dragged around
the screen or something on the screen requires frequent repaints such as
watching a video. 

This is something to do with the power connector. If the AC adapter is plugged
in when the machine boots or resumes from suspend or the screen turns on the
problem occurs and the flicker will happen. Removing the AC adapter does not
remove the flicker, however, if the screen turns on without the AC adapter
present then the AC adapter can be attached without causing the flicker issue.

I need to verify this but I think the flicker happens consistently if the
laptop is in a state of "Charging" with the AC adapter plugged in, too. If it's
"Charged" but the machine is suspended/resumed without the cable in then
plugged in, then the flicker is gone. This may be simply that no power is
actually going to the battery because it's flagged as "charged". It's certainly
a power related issue.

This may also be a related issue: When the power connector is attached the
laptop's temperature is very high even when idle. Without the power cable
connected, the laptop will idle around 50C (as reported by sensors). With the
power cable connected (regardless of whether the charge is 0% or 100%) the cpu
temperature will be 60-65C. The temperature issue does not correlate with the
flicker. Regardless of whether the flicker is happening, the temperature seems
unusually high while the AC adapter is connected.

additional information: I can turn on/off the flicker using radeon dynamic
power management:

echo battery > /sys/class/drm/card0/device/power_dpm_state

No flicker

echo performance > /sys/class/drm/card0/device/power_dpm_state

Flicker starts

By changing the power state to performance the flicker happens. Using "battery"
the flicker does not so it seems to be power related but not obvious. On
"balanced" dpm, the flicker sometimes happens which is probably down to the
power state.

Changing the power state does not seem to affect the temperature at all. 

Adapter: PCI adapter
temp1:        +60.0°C  (crit = +120.0°C, hyst = +90.0°C)

Regardless of the power state the temperature is almost always exactly 60.0,
sometimes it's 59.0 but there is no noticeable temperature difference between
"battery" and "performance" and the clock speed does not seem to change

Regardless of power state, the output of `cat
/sys/kernel/debug/dri/0/radeon_pm_info` shows:

uvd    vclk: 0 dclk: 0
power level 0    sclk: 30000 mclk: 30000 vddc: 900 vddci: 850 pcie gen: 3

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