Hi Souptick,
Thank you for the patch.
On Saturday, 28 July 2018 21:50:58 EEST Souptick Joarder wrote:
> On Sat, Jul 28, 2018 at 11:20 PM, Vaishali Thakkar wrote:
> > On Sat, Jul 28, 2018 at 9:10 PM, Souptick Joarder wrote:
> >> convert drm_atomic_helper_suspend/resume() to use
> >> drm_mode_config_helper_suspend/resume().
> >
> > Hi Souptick,
> >
> > Thanks for your patch.
> >
> >> Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx>
> >> Signed-off-by: Ajit Negi <ajitn.linux@xxxxxxxxx>
> >> ---
> >>
> >> drivers/gpu/drm/rcar-du/rcar_du_drv.c | 21 ++-------------------
> >> 1 file changed, 2 insertions(+), 19 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> >> b/drivers/gpu/drm/rcar-du/rcar_du_drv.c index 02aee6c..288220f 100644
> >> --- a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> >> +++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> >> @@ -357,32 +357,15 @@ static void rcar_du_lastclose(struct drm_device
> >> *dev)
> >>
> >> static int rcar_du_pm_suspend(struct device *dev)
> >> {
> >> struct rcar_du_device *rcdu = dev_get_drvdata(dev);
> >> - struct drm_atomic_state *state;
> >>
> >> - drm_kms_helper_poll_disable(rcdu->ddev);
> >> - drm_fbdev_cma_set_suspend_unlocked(rcdu->fbdev, true);
> >> -
> >> - state = drm_atomic_helper_suspend(rcdu->ddev);
> >> - if (IS_ERR(state)) {
> >> - drm_fbdev_cma_set_suspend_unlocked(rcdu->fbdev, false);
> >
> > I don't think we can use drm_mode_config_helper_(suspend/resume)
> > API here as this file uses CMA functions.
>
> drm_fbdev_cma_set_suspend_unlocked() is wrapper function which
> invokes drm_fb_helper_set_suspend_unlocked().
>
> Where the new API drm_mode_config_helper_suspend/resume() directly invokes
> drm_fb_helper_set_suspend_unlocked(). So it is safe to replace exiting
> code with API drm_mode_config_helper_suspend/resume().
I agree that they're functionally equivalent for now, but what if
drm_fbdev_cma_set_suspend_unlocked() gets extended later ? This change risks
introducing a breakage that could could unnoticed at that point. At the very
least you should add a comment in drm_fbdev_cma_set_suspend_unlocked() to
explain that any extension of the function should also address all drivers
using drm_mode_config_helper_suspend() and drm_mode_config_helper_resume().
> > And from git grep it seems that there are very few drivers using it at the
> > moment, so not sure if introducing new API functions similar to
> > drm_mode_config will make sense or not.
>
> https://www.kernel.org/doc/html/latest/gpu/todo.html
>
> It was picked up from TODO list after discussing with
> Daniel.
>
> > Thanks.
> >
> >> - drm_kms_helper_poll_enable(rcdu->ddev);
> >> - return PTR_ERR(state);
> >> - }
> >> -
> >> - rcdu->suspend_state = state;
Additionally, I think you can remove the suspend_state field from the rcdu
structure.
> >> - return 0;
> >> + return drm_mode_config_helper_suspend(rcdu->ddev);
> >> }
> >>
> >> static int rcar_du_pm_resume(struct device *dev)
> >> {
> >> struct rcar_du_device *rcdu = dev_get_drvdata(dev);
> >>
> >> - drm_atomic_helper_resume(rcdu->ddev, rcdu->suspend_state);
> >> - drm_fbdev_cma_set_suspend_unlocked(rcdu->fbdev, false);
> >> - drm_kms_helper_poll_enable(rcdu->ddev);
> >> -
> >> - return 0;
> >> + return drm_mode_config_helper_resume(rcdu->ddev);
> >> }
> >> #endif
--
Regards,
Laurent Pinchart
