Hi Geert,
On Tuesday, 31 October 2017 15:55:02 EET Geert Uytterhoeven wrote:
> On Tue, Oct 31, 2017 at 2:10 PM, Geert Uytterhoeven wrote:
> > On Tue, Oct 31, 2017 at 2:09 PM, Geert Uytterhoeven wrote:
> >> On Tue, Oct 31, 2017 at 12:27 AM, Rafael J. Wysocki wrote:
> >>> On Monday, October 30, 2017 11:19:08 AM CET Rafael J. Wysocki wrote:
> >>>> On Mon, Oct 30, 2017 at 8:10 AM, Tero Kristo <t-kristo@xxxxxx> wrote:
> >>>>> The recent change to the PM QoS framework to introduce a proper
> >>>>> no constraint value overlooked to handle the devices which don't
> >>>>> implement PM QoS OPS. Runtime PM is one of the more severely
> >>>>> impacted subsystems, failing every attempt to runtime suspend
> >>>>> a device. This leads into some nasty second level issues like
> >>>>> probe failures and increased power consumption among other things.
> >>>>
> >>>> Oh, that's bad.
> >>>>
> >>>> Sorry about breaking it and thanks for the fix!
> >>>>
> >>>>> Fix this by adding a proper return value for devices that don't
> >>>>> implement PM QoS implicitly.
> >>>>>
> >>>>> Fixes: 0cc2b4e5a020 ("PM / QoS: Fix device resume latency PM QoS")
> >>>>> Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
> >>>>> Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >>>>
> >>>> Applied.
> >>>
> >>> And pushed to Linus.
> >>
> >> I'm afraid it is not sufficient.
> >>
> >> Commit 0cc2b4e5a020fc7f ("PM / QoS: Fix device resume latency PM QoS")
> >>
> >> introduced two issues on Renesas platforms:
> >> 1. After boot up, many devices have changed their state from "suspended"
> >> to "active", according to /sys/kernel/debug/pm_genpd/pm_genpd_summary
> >> (comparing that file across boots is one of my standard tests).
> >> Interestingly, doing a system suspend/resume cycle restores their
> >> state to "suspended".
> >>
> >> 2. During system suspend, the following warning is printed on
> >> r8a7791/koelsch:
> >> i2c-rcar e6530000.i2c: runtime PM trying to suspend device but
> >>
> >> active child
>
> 3. I've just bisected a seemingly unrelated issue to the same commit.
> On Salvator-XS with R-Car H3, initialization of the rcar-du driver now
> takes more than 1 minute due to flip_done time outs, while it took 0.12s
> before:
>
> [ 3.015035] [drm] Supports vblank timestamp caching Rev 2
> (21.10.2013). [ 3.021721] [drm] No driver support for vblank timestamp
> query. [ 13.280738] [drm:drm_atomic_helper_wait_for_flip_done] *ERROR*
> [CRTC:58:crtc-3] flip_done timed out
> [ 23.520707] [drm:drm_atomic_helper_commit_cleanup_done] *ERROR*
> [CRTC:58:crtc-3] flip_done timed out
> [ 33.760708] [drm:drm_atomic_helper_wait_for_flip_done] *ERROR*
> [CRTC:58:crtc-3] flip_done timed out
> [ 44.000755] [drm:drm_atomic_helper_commit_cleanup_done] *ERROR*
> [CRTC:58:crtc-3] flip_done timed out
> [ 44.003597] Console: switching to colour frame buffer device 128x48
> [ 54.240707] [drm:drm_atomic_helper_wait_for_flip_done] *ERROR*
> [CRTC:58:crtc-3] flip_done timed out
> [ 64.480706] [drm:drm_atomic_helper_commit_cleanup_done] *ERROR*
> [CRTC:58:crtc-3] flip_done timed out
> [ 64.544876] rcar-du feb00000.display: fb0: frame buffer device
> [ 64.552013] [drm] Initialized rcar-du 1.0.0 20130110 for
> feb00000.display on minor 0
> [ 64.559873] [drm] Device feb00000.display probed
>
> >> Commit 2a9a86d5c81389cd ("PM / QoS: Fix default runtime_pm device resume
> >> latency") fixes the second issue, but not the first.
>
> ... nor the third.
>
> >> Reverting commits 2a9a86d5c81389cd ("PM / QoS: Fix default runtime_pm
> >> device resume latency") and 0cc2b4e5a020fc7f ("PM / QoS: Fix device
> >> resume
> >> latency PM QoS") fixes both.
>
> ... all three.
Thank you for tracking this and notifying me. I like it even better now that
the problem seems to be fixed without requiring any action from my side :-)
> >> Do you have a clue?
> >> Thanks!
--
Regards,
Laurent Pinchart
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