26.06.2020 10:48, Thierry Reding пишет: > On Wed, Jun 24, 2020 at 06:08:47PM +0300, Dmitry Osipenko wrote: >> VDE partition is left turned ON after bootloader on most devices, hence >> let's ensure that it's turned OFF in order to lower power leakage while >> hardware is idling by turning it ON and OFF during of the driver's probe. >> >> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx> >> --- >> drivers/staging/media/tegra-vde/vde.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/drivers/staging/media/tegra-vde/vde.c b/drivers/staging/media/tegra-vde/vde.c >> index b64e35b86fb4..3be96c36bf43 100644 >> --- a/drivers/staging/media/tegra-vde/vde.c >> +++ b/drivers/staging/media/tegra-vde/vde.c >> @@ -1068,6 +1068,14 @@ static int tegra_vde_probe(struct platform_device *pdev) >> pm_runtime_use_autosuspend(dev); >> pm_runtime_set_autosuspend_delay(dev, 300); >> >> + /* >> + * VDE partition may be left ON after bootloader, hence let's >> + * power-cycle it in order to put hardware into a predictable lower >> + * power state. >> + */ >> + pm_runtime_get_sync(dev); >> + pm_runtime_put(dev); >> + >> return 0; >> >> err_deinit_iommu: > > Shouldn't this happen automatically? My understanding is that power > domains are turned on automatically before ->probe() and then unless a > runtime PM reference is taken during ->probe() it will get turned off > again after ->probe()? Older Tegra SoCs haven't been converted to use the generic power-domain API and today's VDE driver supports only T20 and T30 SoCs. > Is that not happening? Is auto-suspend perhaps getting in the way > somehow? We're manually toggling the PD using legacy Tegra-PD API in the driver's RPM callbacks, that's why the RPM needs to be toggled manually as well. Perhaps this hunk could be removed if older Tergas would get a genpd support. I guess it shouldn't be difficult to implement the genpd support, but then there will be a compatibility trouble with older DTs, so perhaps it's not really worth the effort.
