Re: [PATCH] rpmsg: core: add support to power domains for devices

From: Suman Anna
Date: Mon Sep 24 2018 - 20:25:38 EST


Hi Srinivas,

On 06/15/2018 04:59 AM, Srinivas Kandagatla wrote:
> Some of the rpmsg devices need to switch on power domains to communicate
> with remote processor. For example on Qualcomm DB820c platform LPASS
> power domain needs to switched on for any kind of audio services.
> This patch adds the missing power domain support in rpmsg core.
>
> Without this patch attempting to play audio via QDSP on DB820c would
> reboot the system.
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> ---
> drivers/rpmsg/rpmsg_core.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
> index b714a543a91d..8122807db380 100644
> --- a/drivers/rpmsg/rpmsg_core.c
> +++ b/drivers/rpmsg/rpmsg_core.c
> @@ -15,6 +15,7 @@
> #include <linux/module.h>
> #include <linux/rpmsg.h>
> #include <linux/of_device.h>
> +#include <linux/pm_domain.h>
> #include <linux/slab.h>
>
> #include "rpmsg_internal.h"
> @@ -449,6 +450,10 @@ static int rpmsg_dev_probe(struct device *dev)
> struct rpmsg_endpoint *ept = NULL;
> int err;
>
> + err = dev_pm_domain_attach(dev, true);
> + if (err)
> + goto out;

This patch has broken the virtio-rpmsg stack based rpmsg devices. These
devices are non-DT and the rpmsg_dev_probe() is now failing with -19
(-ENODEV) error code.

Loic, Arnaud,
Can one of you double-confirm this behavior on ST platforms as well?
The patch came through 4.14.71 stable release and broke our downstream
kernels.

regards
Suman

> +
> if (rpdrv->callback) {
> strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
> chinfo.src = rpdev->src;
> @@ -490,6 +495,8 @@ static int rpmsg_dev_remove(struct device *dev)
>
> rpdrv->remove(rpdev);
>
> + dev_pm_domain_detach(dev, true);
> +
> if (rpdev->ept)
> rpmsg_destroy_ept(rpdev->ept);
>
>