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

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Date:   Mon, 24 Sep 2018 19:25:31 -0500
From:   Suman Anna <s-anna@...com>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        <ohad@...ery.com>, <bjorn.andersson@...aro.org>
CC:     <linux-remoteproc@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Loic Pallardy <loic.pallardy@...com>,
        Arnaud POULIQUEN <arnaud.pouliquen@...com>
Subject: Re: [PATCH] rpmsg: core: add support to power domains for devices

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@...aro.org>
> ---
>  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);
>  
>