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

From: Srinivas Kandagatla
Date: Tue Sep 25 2018 - 04:29:57 EST


Hi Suman,

On 25/09/18 01:25, Suman Anna wrote:
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.


There seems to be some dependency on this patch ( https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v4.19-rc5&id=919b7308fcc452cd4e282bab389c33384a9f3790 ) which seems to rework the return values from acpi_dev_pm_attach() and genpd_dev_pm_attach()



--srini


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);