[PATCH] HID: rmi: Make sure the HID device is opened on resume

So it looks like that suspend/resume has actually always been broken on
hid-rmi. The fact it worked was a rather silly coincidence that was
relying on the HID device to already be opened upon resume. This means
that so long as anything was reading the /dev/input/eventX node for for
an RMI device, it would suspend and resume correctly. As well, if
nothing happened to be keeping the HID device away it would shut off,
then the RMI driver would get confused on resume when it stopped
responding and explode.

So, call hid_hw_open() in rmi_post_resume() so we make sure that the
device is alive before we try talking to it.

This fixes RMI device suspend/resume over HID.

Signed-off-by: Lyude <lyude@redhat.com>
Cc: Andrew Duggan <redacted>
Cc: stable@vger.kernel.org
---
 drivers/hid/hid-rmi.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
index 5b40c2614599..e7d124f9a27f 100644
--- a/drivers/hid/hid-rmi.c
+++ b/drivers/hid/hid-rmi.c

@@ -431,22 +431,29 @@ static int rmi_post_resume(struct hid_device *hdev)
 {
 	struct rmi_data *data = hid_get_drvdata(hdev);
 	struct rmi_device *rmi_dev = data->xport.rmi_dev;
-	int ret;
+	int ret = 0;
 
 	if (!(data->device_flags & RMI_DEVICE))
 		return 0;
 
-	ret = rmi_reset_attn_mode(hdev);
+	/* Make sure the HID device is ready to receive events */
+	ret = hid_hw_open(hdev);
 	if (ret)
 		return ret;
 
+	ret = rmi_reset_attn_mode(hdev);
+	if (ret)
+		goto out;
+
 	ret = rmi_driver_resume(rmi_dev, false);
 	if (ret) {
 		hid_warn(hdev, "Failed to resume device: %d\n", ret);
-		return ret;
+		goto out;
 	}
 
-	return 0;
+out:
+	hid_hw_close(hdev);
+	return ret;
 }
 #endif /* CONFIG_PM */
 

-- 
2.13.3

On Sun, Jul 23, 2017 at 4:15 AM, Lyude [off-list ref] wrote:

So, call hid_hw_open() in rmi_post_resume() so we make sure that the
device is alive before we try talking to it.

This fixes RMI device suspend/resume over HID.

-       int ret;
+       int ret = 0;

What's the point?

-- 
With Best Regards,
Andy Shevchenko

On Jul 22 2017 or thereabouts, Lyude wrote:

So it looks like that suspend/resume has actually always been broken on
hid-rmi. The fact it worked was a rather silly coincidence that was
relying on the HID device to already be opened upon resume. This means
that so long as anything was reading the /dev/input/eventX node for for
an RMI device, it would suspend and resume correctly. As well, if
nothing happened to be keeping the HID device away it would shut off,
then the RMI driver would get confused on resume when it stopped
responding and explode.

Oh, good finding. However, given that there are few other drivers not
calling hid_hw_open during their .reset_resume() callback and those
drivers also are communicating with the device, I wonder if we should
not have something more generic, that will call hid_hw_open/close in the
transport layer directly.

I do not recall having seen bugs for Wacom devices, so maybe this is
something i2c-hid related, but it wouldn't hurt I guess to open/close
the device before calling reset_resume.

Cheers,
Benjamin

On Sun, 2017-07-23 at 12:54 +0300, Andy Shevchenko wrote:

On Sun, Jul 23, 2017 at 4:15 AM, Lyude [off-list ref] wrote:

quoted

So, call hid_hw_open() in rmi_post_resume() so we make sure that
the
device is alive before we try talking to it.

This fixes RMI device suspend/resume over HID.
-       int ret;
+       int ret = 0;

What's the point?

So that we can use the same out: label at the end of the function that
calls hid_hw_close() to return success. This being said though I just
realized that setting ret will initialize it to 0 anyway, so I guess
this can be dropped

quoted

        if (!(data->device_flags & RMI_DEVICE))
                return 0;

-       ret = rmi_reset_attn_mode(hdev);
+       /* Make sure the HID device is ready to receive events */
+       ret = hid_hw_open(hdev);
        if (ret)
                return ret;

On Mon, 2017-07-24 at 10:15 +0200, Benjamin Tissoires wrote:

On Jul 22 2017 or thereabouts, Lyude wrote:

quoted

So it looks like that suspend/resume has actually always been
broken on
hid-rmi. The fact it worked was a rather silly coincidence that was
relying on the HID device to already be opened upon resume. This
means
that so long as anything was reading the /dev/input/eventX node for
for
an RMI device, it would suspend and resume correctly. As well, if
nothing happened to be keeping the HID device away it would shut
off,
then the RMI driver would get confused on resume when it stopped
responding and explode.

Oh, good finding. However, given that there are few other drivers not
calling hid_hw_open during their .reset_resume() callback and those
drivers also are communicating with the device, I wonder if we should
not have something more generic, that will call hid_hw_open/close in
the
transport layer directly.

This sounds like a good idea, especially since a call like this is
rather easy to miss. I will look into doing that for v2

I do not recall having seen bugs for Wacom devices, so maybe this is
something i2c-hid related, but it wouldn't hurt I guess to open/close
the device before calling reset_resume.

Cheers,
Benjamin

quoted

So, call hid_hw_open() in rmi_post_resume() so we make sure that
the
device is alive before we try talking to it.

This fixes RMI device suspend/resume over HID.

Signed-off-by: Lyude <lyude@redhat.com>
Cc: Andrew Duggan <redacted>
Cc: stable@vger.kernel.org
---
 drivers/hid/hid-rmi.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
index 5b40c2614599..e7d124f9a27f 100644
--- a/drivers/hid/hid-rmi.c
+++ b/drivers/hid/hid-rmi.c

@@ -431,22 +431,29 @@ static int rmi_post_resume(struct hid_device

*hdev)
 {
 	struct rmi_data *data = hid_get_drvdata(hdev);
 	struct rmi_device *rmi_dev = data->xport.rmi_dev;
-	int ret;
+	int ret = 0;
 
 	if (!(data->device_flags & RMI_DEVICE))
 		return 0;
 
-	ret = rmi_reset_attn_mode(hdev);
+	/* Make sure the HID device is ready to receive events */
+	ret = hid_hw_open(hdev);
 	if (ret)
 		return ret;
 
+	ret = rmi_reset_attn_mode(hdev);
+	if (ret)
+		goto out;
+
 	ret = rmi_driver_resume(rmi_dev, false);
 	if (ret) {
 		hid_warn(hdev, "Failed to resume device: %d\n",
ret);
-		return ret;
+		goto out;
 	}
 
-	return 0;
+out:
+	hid_hw_close(hdev);
+	return ret;
 }
 #endif /* CONFIG_PM */
 
-- 
2.13.3

On Mon, 24 Jul 2017, Lyude Paul wrote:

quoted

quoted

So, call hid_hw_open() in rmi_post_resume() so we make sure that
the
device is alive before we try talking to it.

This fixes RMI device suspend/resume over HID.
-       int ret;
+       int ret = 0;

What's the point?

So that we can use the same out: label at the end of the function that
calls hid_hw_close() to return success. This being said though I just
realized that setting ret will initialize it to 0 anyway, so I guess
this can be dropped

Andy's point was that hid_hw_open() is obviously re-initializing the ret 
before its first use as a return value, so there is no need to initialize 
it at a declaration time.

-- 
Jiri Kosina
SUSE Labs

Yeah I noticed that, sorry if my response wasn't very clear! Should
probably wait to have my morning coffee before responding to these
messages :P

On Mon, 2017-07-24 at 21:28 +0200, Jiri Kosina wrote:

On Mon, 24 Jul 2017, Lyude Paul wrote:

quoted

quoted

quoted

So, call hid_hw_open() in rmi_post_resume() so we make sure
that
the
device is alive before we try talking to it.

This fixes RMI device suspend/resume over HID.
-       int ret;
+       int ret = 0;

What's the point?

So that we can use the same out: label at the end of the function
that
calls hid_hw_close() to return success. This being said though I
just
realized that setting ret will initialize it to 0 anyway, so I
guess
this can be dropped

Andy's point was that hid_hw_open() is obviously re-initializing the
ret 
before its first use as a return value, so there is no need to
initialize 
it at a declaration time.

On Jul 24 2017 or thereabouts, Lyude Paul wrote:

On Mon, 2017-07-24 at 10:15 +0200, Benjamin Tissoires wrote:

quoted

On Jul 22 2017 or thereabouts, Lyude wrote:

quoted

So it looks like that suspend/resume has actually always been
broken on
hid-rmi. The fact it worked was a rather silly coincidence that was
relying on the HID device to already be opened upon resume. This
means
that so long as anything was reading the /dev/input/eventX node for
for
an RMI device, it would suspend and resume correctly. As well, if
nothing happened to be keeping the HID device away it would shut
off,
then the RMI driver would get confused on resume when it stopped
responding and explode.

Oh, good finding. However, given that there are few other drivers not
calling hid_hw_open during their .reset_resume() callback and those
drivers also are communicating with the device, I wonder if we should
not have something more generic, that will call hid_hw_open/close in
the
transport layer directly.

This sounds like a good idea, especially since a call like this is
rather easy to miss. I will look into doing that for v2

I know I requested a v2, but meanwhile some users are experiencing
delays at resume:
https://bugzilla.kernel.org/show_bug.cgi?id=196851

Jiri, could you take this one in v4.14 (maybe with @stable) and we'll
figure out a way to fix this properly later (looks like the .resume and
.reset_resume are called from the transport drivers, not hid-core, so we
might need a little bit of testing).

In its current form (with the nitpick Andy noticed):
Reviewed-by: Benjamin Tissoires <redacted>

Cheers,
Benjamin

quoted

I do not recall having seen bugs for Wacom devices, so maybe this is
something i2c-hid related, but it wouldn't hurt I guess to open/close
the device before calling reset_resume.

Cheers,
Benjamin

quoted

So, call hid_hw_open() in rmi_post_resume() so we make sure that
the
device is alive before we try talking to it.

This fixes RMI device suspend/resume over HID.

Signed-off-by: Lyude <lyude@redhat.com>
Cc: Andrew Duggan <redacted>
Cc: stable@vger.kernel.org
---
 drivers/hid/hid-rmi.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
index 5b40c2614599..e7d124f9a27f 100644
--- a/drivers/hid/hid-rmi.c
+++ b/drivers/hid/hid-rmi.c

@@ -431,22 +431,29 @@ static int rmi_post_resume(struct hid_device

*hdev)
 {
 	struct rmi_data *data = hid_get_drvdata(hdev);
 	struct rmi_device *rmi_dev = data->xport.rmi_dev;
-	int ret;
+	int ret = 0;
 
 	if (!(data->device_flags & RMI_DEVICE))
 		return 0;
 
-	ret = rmi_reset_attn_mode(hdev);
+	/* Make sure the HID device is ready to receive events */
+	ret = hid_hw_open(hdev);
 	if (ret)
 		return ret;
 
+	ret = rmi_reset_attn_mode(hdev);
+	if (ret)
+		goto out;
+
 	ret = rmi_driver_resume(rmi_dev, false);
 	if (ret) {
 		hid_warn(hdev, "Failed to resume device: %d\n",
ret);
-		return ret;
+		goto out;
 	}
 
-	return 0;
+out:
+	hid_hw_close(hdev);
+	return ret;
 }
 #endif /* CONFIG_PM */
 
-- 
2.13.3

On Fri, 8 Sep 2017, Benjamin Tissoires wrote:

I know I requested a v2, but meanwhile some users are experiencing
delays at resume:
https://bugzilla.kernel.org/show_bug.cgi?id=196851

Jiri, could you take this one in v4.14 (maybe with @stable) and we'll
figure out a way to fix this properly later (looks like the .resume and
.reset_resume are called from the transport drivers, not hid-core, so we
might need a little bit of testing).

In its current form (with the nitpick Andy noticed):
Reviewed-by: Benjamin Tissoires <redacted>

Ok, makes sense. Now applied to for-4.14/upstream-fixes. Thanks,

-- 
Jiri Kosina
SUSE Labs