lkml.org 
[lkml]   [2020]   [Jun]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 4/4] media: staging: tegra-vde: Power-cycle hardware on probe
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@gmail.com>
> ---
> 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()?

Is that not happening? Is auto-suspend perhaps getting in the way
somehow?

Thierry
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2020-06-26 09:49    [W:0.078 / U:0.276 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site