[PATCH] drm/stm: repair runtime power management

[Benjamin Gaignard]

Le jeu. 2 juil. 2020 à 14:31, Philippe CORNU <philippe.cornu at st.com> a écrit :
>
>
>
> On 2/29/20 11:16 PM, Marek Vasut wrote:
> > Add missing pm_runtime_get_sync() into ltdc_crtc_atomic_enable() to
> > match pm_runtime_put_sync() in ltdc_crtc_atomic_disable(), otherwise
> > the LTDC might suspend via runtime PM, disable clock, and then fail
> > to resume later on.
> >
> > The test which triggers it is roughly -- run qt5 application which
> > uses eglfs platform and etnaviv, stop the application, sleep for 15
> > minutes, run the application again. This leads to a timeout waiting
> > for vsync, because the LTDC has suspended, but did not resume.
> >
> > Fixes: 35ab6cfbf211 ("drm/stm: support runtime power management")
> > Signed-off-by: Marek Vasut <marex at denx.de>
> > Cc: Yannick Fertré <yannick.fertre at st.com>
> > Cc: Philippe Cornu <philippe.cornu at st.com>
> > Cc: Benjamin Gaignard <benjamin.gaignard at linaro.org>
> > Cc: Vincent Abriou <vincent.abriou at st.com>
> > Cc: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
> > Cc: Alexandre Torgue <alexandre.torgue at st.com>
> > To: dri-devel at lists.freedesktop.org
> > Cc: linux-stm32 at st-md-mailman.stormreply.com
> > Cc: linux-arm-kernel at lists.infradead.org
> > ---
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 297 at drivers/gpu/drm/drm_atomic_helper.c:1494 drm_atomic_helper_wait_for_vblanks+0x1dc/0x200
> > [CRTC:35:crtc-0] vblank wait timed out
> > Modules linked in:
> > CPU: 0 PID: 297 Comm: QSGRenderThread Not tainted 5.6.0-rc3-next-20200228-00010-g318bf0fc08ef #2
> > Hardware name: STM32 (Device Tree Support)
> > [<c010f18c>] (unwind_backtrace) from [<c010afb8>] (show_stack+0x10/0x14)
> > [<c010afb8>] (show_stack) from [<c07b1d3c>] (dump_stack+0xb4/0xd0)
> > [<c07b1d3c>] (dump_stack) from [<c011d8b8>] (__warn+0xd4/0xf0)
> > [<c011d8b8>] (__warn) from [<c011dc4c>] (warn_slowpath_fmt+0x78/0xa8)
> > [<c011dc4c>] (warn_slowpath_fmt) from [<c04a266c>] (drm_atomic_helper_wait_for_vblanks+0x1dc/0x200)
> > [<c04a266c>] (drm_atomic_helper_wait_for_vblanks) from [<c04a510c>] (drm_atomic_helper_commit_tail+0
> > x50/0x60)
> > [<c04a510c>] (drm_atomic_helper_commit_tail) from [<c04a52a8>] (commit_tail+0x12c/0x13c)
> > [<c04a52a8>] (commit_tail) from [<c04a53b4>] (drm_atomic_helper_commit+0xf4/0x100)
> > [<c04a53b4>] (drm_atomic_helper_commit) from [<c04a2d38>] (drm_atomic_helper_set_config+0x58/0x6c)
> > [<c04a2d38>] (drm_atomic_helper_set_config) from [<c04b1994>] (drm_mode_setcrtc+0x450/0x550)
> > [<c04b1994>] (drm_mode_setcrtc) from [<c04ad570>] (drm_ioctl_kernel+0x90/0xe8)
> > [<c04ad570>] (drm_ioctl_kernel) from [<c04ad8ac>] (drm_ioctl+0x2e4/0x32c)
> > [<c04ad8ac>] (drm_ioctl) from [<c0246784>] (vfs_ioctl+0x20/0x38)
> > [<c0246784>] (vfs_ioctl) from [<c02470f0>] (ksys_ioctl+0xbc/0x7b0)
> > [<c02470f0>] (ksys_ioctl) from [<c0101000>] (ret_fast_syscall+0x0/0x54)
> > Exception stack(0xee8f3fa8 to 0xee8f3ff0)
> > 3fa0:                   00000005 adcbeb18 00000005 c06864a2 adcbeb18 00000001
> > 3fc0: 00000005 adcbeb18 c06864a2 00000036 00000029 00000023 00000023 00000007
> > 3fe0: b113b098 adcbeafc b1125413 b6155cf8
> > ---[ end trace 2ad5ba954ceb767a ]---
> > ---
> >   drivers/gpu/drm/stm/ltdc.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> > index 99bf93e8b36f..301de0498078 100644
> > --- a/drivers/gpu/drm/stm/ltdc.c
> > +++ b/drivers/gpu/drm/stm/ltdc.c
> > @@ -425,9 +425,12 @@ static void ltdc_crtc_atomic_enable(struct drm_crtc *crtc,
> >                                   struct drm_crtc_state *old_state)
> >   {
> >       struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> > +     struct drm_device *ddev = crtc->dev;
> >
> >       DRM_DEBUG_DRIVER("\n");
> >
> > +     pm_runtime_get_sync(ddev->dev);
> > +
> >       /* Sets the background color value */
> >       reg_write(ldev->regs, LTDC_BCCR, BCCR_BCBLACK);
> >
> >
> Hi Marek,
> Many thanks for your patch,
> Acked-by: Philippe Cornu <philippe.cornu at st.com>
> Tested-by: Yannick Fertre <yannick.fertre at st.com>
>
>
> Hi Benjamin,
> Could you please apply "drm/stm: ltdc: remove call of pm-runtime
> functions" **before** this one. Thank you.

Applied on drm-misc-next.

Thanks,
Benjamin

>
> Philippe :-)