Hi Laurent,
On Fri, Jun 23, 2023 at 5:34 PM Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
> On Fri, Jun 23, 2023 at 05:22:45PM +0200, Geert Uytterhoeven wrote:
> > On Fri, Jun 23, 2023 at 5:11 PM Laurent Pinchart wrote:
> > > On Fri, Jun 23, 2023 at 06:07:44PM +0300, Laurent Pinchart wrote:
> > > > On Thu, Jun 22, 2023 at 11:21:18AM +0200, Geert Uytterhoeven wrote:
> > > > > The SH-Mobile LCD Controller is part of a PM Domain on all relevant SoCs
> > > > > (clock domain on all, power domain on some). Hence it may not be
> > > > > sufficient to manage the LCDC module clock explicitly (e.g. if the
> > > > > selected clock source differs from SHMOB_DRM_CLK_BUS).
> > > > >
> > > > > Fix this by using Runtime PM instead.
> > > > >
> > > > > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> > > > > ---
> > > > > drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c | 11 ++++++++++-
> > > > > drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c | 5 +++++
> > > > > 2 files changed, 15 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> > > > > index fbfd906844da490c..84dbf35025d7be63 100644
> > > > > --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> > > > > +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> > > > > @@ -9,6 +9,7 @@
> > > > >
> > > > > #include <linux/backlight.h>
> > > > > #include <linux/clk.h>
> > > > > +#include <linux/pm_runtime.h>
> > > > >
> > > > > #include <drm/drm_crtc.h>
> > > > > #include <drm/drm_crtc_helper.h>
> > > > > @@ -170,10 +171,16 @@ static void shmob_drm_crtc_start(struct shmob_drm_crtc *scrtc)
> > > > > if (WARN_ON(format == NULL))
> > > > > return;
> > > > >
> > > > > + ret = pm_runtime_resume_and_get(sdev->dev);
> > > > > + if (ret)
> > > > > + return;
> > > > > +
> > > > > /* Enable clocks before accessing the hardware. */
> > > > > ret = shmob_drm_clk_on(sdev);
> > > >
> > > > This would be best located in the runtime PM resume handler. Same for
> > > > disabling clocks in the runtime PM suspend handler.
> > >
> > > The driver should then depend on CONFIG_PM. There's no indirect
> > > dependency through CONFIG_DRM as far as I can tell, but there's one
> > > through ARCH_SHMOBILE. This then got me puzzled, as ARCH_SHMOBILE is
> > > defined in arch/sh/Kconfig, and this driver depends on ARM. Am I missing
> > > something ?
> >
> > Vommit 4bd65789ba847f39 ("drm: shmobile: Make DRM_SHMOBILE visible on
> > Renesas SoC platforms") in drm-next:
> >
> > - depends on DRM && ARM
> > - depends on ARCH_SHMOBILE || COMPILE_TEST
> > + depends on DRM
> > + depends on ARCH_RENESAS || ARCH_SHMOBILE || COMPILE_TEST
>
> That's better indeed :-)
>
> A dependency on CONFIG_PM is still needed as ARCH_RENESAS doesn't depend
> on it.
ARCH_RMOBILE selects PM, so PM will be enabled on affected platforms.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
