[PATCH] HID: i2c-hid: Add a small delay after powering on/off the device

[PATCH] HID: i2c-hid: Add a small delay after powering on/off the device

[Kai-Heng Feng]

Raydium touchpanel (2386:4B33) sometimes does not workin desktop session
although it works in display manager.

During user logging, the display manager exits, close the HID device,
then the device gets runtime suspended and powered off. The desktop
session begins shortly after, opens the HID device, then the device gets
runtime resumed and powered on.

If the trasition from display manager to desktop sesesion is fast, the
touchpanel cannot switch from powered off to powered on in short
timeframe. So add a small delay to workaround the issue.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/hid/i2c-hid/i2c-hid.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index f3076659361a..ff5682cc1bce 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -409,6 +409,8 @@ static int i2c_hid_set_power(struct i2c_client *client, int power_state)
 
 	if (ret)
 		dev_err(&client->dev, "failed to change power setting.\n");
+	else
+		msleep(20);
 
 set_pwr_exit:
 	return ret;
-- 
2.17.1

Re: [PATCH] HID: i2c-hid: Add a small delay after powering on/off the device

[Benjamin Tissoires]

On Mon, Oct 1, 2018 at 5:53 AM Kai-Heng Feng
<kai.heng.feng@canonical.com> wrote:
>
> Raydium touchpanel (2386:4B33) sometimes does not workin desktop session
> although it works in display manager.
>
> During user logging, the display manager exits, close the HID device,
> then the device gets runtime suspended and powered off. The desktop
> session begins shortly after, opens the HID device, then the device gets
> runtime resumed and powered on.
>
> If the trasition from display manager to desktop sesesion is fast, the
> touchpanel cannot switch from powered off to powered on in short
> timeframe. So add a small delay to workaround the issue.

I think you want something similar to
https://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid.git/commit/?h=for-next&id=807588ac92018bde88a1958f546438e840eb0158

>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
>  drivers/hid/i2c-hid/i2c-hid.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index f3076659361a..ff5682cc1bce 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -409,6 +409,8 @@ static int i2c_hid_set_power(struct i2c_client *client, int power_state)
>
>         if (ret)
>                 dev_err(&client->dev, "failed to change power setting.\n");
> +       else
> +               msleep(20);

We shouldn't have this error in the first place, so adding a timeout
will just add a band-aid on top of an other issue.

I really think the solution from Anisse would work in your case and
will be nicer.

Cheers,
Benjamin

>
>  set_pwr_exit:
>         return ret;
> --
> 2.17.1
>

Re: [PATCH] HID: i2c-hid: Add a small delay after powering on/off the device

[Kai Heng Feng]

> On Oct 1, 2018, at 3:00 PM, Benjamin Tissoires  
> <benjamin.tissoires@redhat.com> wrote:
>
> On Mon, Oct 1, 2018 at 5:53 AM Kai-Heng Feng
> <kai.heng.feng@canonical.com> wrote:
>> Raydium touchpanel (2386:4B33) sometimes does not workin desktop session
>> although it works in display manager.
>>
>> During user logging, the display manager exits, close the HID device,
>> then the device gets runtime suspended and powered off. The desktop
>> session begins shortly after, opens the HID device, then the device gets
>> runtime resumed and powered on.
>>
>> If the trasition from display manager to desktop sesesion is fast, the
>> touchpanel cannot switch from powered off to powered on in short
>> timeframe. So add a small delay to workaround the issue.
>
> I think you want something similar to
> https://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid.git/commit/?h=for-next&id=807588ac92018bde88a1958f546438e840eb0158
>
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>> ---
>>  drivers/hid/i2c-hid/i2c-hid.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
>> index f3076659361a..ff5682cc1bce 100644
>> --- a/drivers/hid/i2c-hid/i2c-hid.c
>> +++ b/drivers/hid/i2c-hid/i2c-hid.c
>> @@ -409,6 +409,8 @@ static int i2c_hid_set_power(struct i2c_client  
>> *client, int power_state)
>>
>>         if (ret)
>>                 dev_err(&client->dev, "failed to change power setting.\n");
>> +       else
>> +               msleep(20);
>
> We shouldn't have this error in the first place, so adding a timeout
> will just add a band-aid on top of an other issue.
>
> I really think the solution from Anisse would work in your case and
> will be nicer.

The Hantick one requires 2.5 seconds delay, the Raydium one requires much  
less.
Also it doesn't have the input shift issue.

So disabling runtime PM entirely is a little overkill in this case.

Maybe there's a better approach?

Kai-Heng

>
> Cheers,
> Benjamin
>
>>  set_pwr_exit:
>>         return ret;
>> --
>> 2.17.1

Re: [PATCH] HID: i2c-hid: Add a small delay after powering on/off the device

[Jiri Kosina]

On Mon, 1 Oct 2018, Kai-Heng Feng wrote:

> Raydium touchpanel (2386:4B33) sometimes does not workin desktop session
> although it works in display manager.
> 
> During user logging, the display manager exits, close the HID device,
> then the device gets runtime suspended and powered off. The desktop
> session begins shortly after, opens the HID device, then the device gets
> runtime resumed and powered on.
> 
> If the trasition from display manager to desktop sesesion is fast, the
> touchpanel cannot switch from powered off to powered on in short
> timeframe. So add a small delay to workaround the issue.
> 
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
>  drivers/hid/i2c-hid/i2c-hid.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index f3076659361a..ff5682cc1bce 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -409,6 +409,8 @@ static int i2c_hid_set_power(struct i2c_client *client, int power_state)
>  
>  	if (ret)
>  		dev_err(&client->dev, "failed to change power setting.\n");
> +	else
> +		msleep(20);

In case there really is no other way around it, at least please add 
comment explaining why this ugly msleep() is there. Thanks,

-- 
Jiri Kosina
SUSE Labs

Re: [PATCH] HID: i2c-hid: Add a small delay after powering on/off the device

[Kai Heng Feng]

> On Oct 3, 2018, at 5:10 PM, Jiri Kosina <jikos@kernel.org> wrote:
> 
> On Mon, 1 Oct 2018, Kai-Heng Feng wrote:
> 
>> Raydium touchpanel (2386:4B33) sometimes does not workin desktop session
>> although it works in display manager.
>> 
>> During user logging, the display manager exits, close the HID device,
>> then the device gets runtime suspended and powered off. The desktop
>> session begins shortly after, opens the HID device, then the device gets
>> runtime resumed and powered on.
>> 
>> If the trasition from display manager to desktop sesesion is fast, the
>> touchpanel cannot switch from powered off to powered on in short
>> timeframe. So add a small delay to workaround the issue.
>> 
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>> ---
>> drivers/hid/i2c-hid/i2c-hid.c | 2 ++
>> 1 file changed, 2 insertions(+)
>> 
>> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
>> index f3076659361a..ff5682cc1bce 100644
>> --- a/drivers/hid/i2c-hid/i2c-hid.c
>> +++ b/drivers/hid/i2c-hid/i2c-hid.c
>> @@ -409,6 +409,8 @@ static int i2c_hid_set_power(struct i2c_client *client, int power_state)
>> 
>> 	if (ret)
>> 		dev_err(&client->dev, "failed to change power setting.\n");
>> +	else
>> +		msleep(20);
> 
> In case there really is no other way around it, at least please add 
> comment explaining why this ugly msleep() is there. Thanks,

I am working on a better approach for this issue, I’ll send a v2 soon.

Kai-Heng

> 
> -- 
> Jiri Kosina
> SUSE Labs
>