[PATCH v3] Input: synaptics-rmi4 - retry reading SMBus version on resume

[PATCH v3] Input: synaptics-rmi4 - retry reading SMBus version on resume

[Jeffery Miller]

On resume there can be a period of time after the
preceding serio_resume -> psmouse_deactivate call
where calls to rmi_smb_get_version fail with
-ENXIO.

The call path in rmi_smb_resume is rmi_smb_resume -> rmi_smb_reset ->
rmi_smb_enable_smbus_mode -> rmi_smb_get_version where
this failure would occur.

Add a 30ms delay and retry in the ENXIO case to ensure the following
rmi_driver_resume calls in rmi_smbus_resume can succeed.

This behavior was seen on a Lenovo T440p machine that required
a delay of approximately 7-12ms.

The 30ms delay was chosen based on the linux-input message:
Link: https://lore.kernel.org/all/BYAPR03MB47572F2C65E52ED673238D41B2439@BYAPR03MB4757.namprd03.prod.outlook.com/

With this patch the trimmed resume logs look similar to:
```
psmouse serio1: PM: calling serio_resume+0x0/0x8c @ 5399, parent: i8042
[5399] libps2:__ps2_command:316: psmouse serio1: f5 [] - 0/00000000 []
psmouse serio1: PM: serio_resume+0x0/0x8c returned 0 after 3259 usecs
...
rmi4_smbus 0-002c: PM: calling rmi_smb_resume ... @ 5454, parent: i2c-0
...
[5454] i2c_i801:i801_check_post:414: i801_smbus 0000:00:1f.3: No response
smbus_result: i2c-0 a=02c f=0000 c=fd BYTE_DATA rd res=-6
rmi4_smbus 0-002c: failed to get SMBus version number!
rmi4_smbus 0-002c: sleeping to retry getting the SMBus version number
...
rmi4_smbus 0-002c: PM: rmi_smb_resume ... returned 0 after 41351 usecs
```

Signed-off-by: Jeffery Miller <jefferymiller@google.com>
---

Early boot dmesg include:
```
rmi4_smbus 0-002c: registering SMbus-connected sensor
rmi4_f01 rmi4-00.fn01: found RMI device, manufacturer: Synaptics, product: TM2722-001, fw id: 0
```

The resume order looks correct. The `psmouse serio1` resume returns
before the rmi_smb_resume is called showing the patch from
https://lore.kernel.org/all/89456fcd-a113-4c82-4b10-a9bcaefac68f@google.com/
is applied and working for that ordering.

I attempted to try to rule out some interaction between the concurrent
input resume calls for other i8042 devices.
Adding a 7ms delay after psmouse_deactivate which is called in the
preceding psmouse serio1 serio_resume function also allows
this version call to succeed.

If the rmi_smb_probe device_disable_async_suspend patch is applied
it will also avoid this issue. However the time between
the psmouse_deactivate call for serio_resume and rmi_smb_resume
was over 60ms on my test machine. This would naturally be long
enough to avoid this particular delay.


Changes in v3:
- Tagged mail message Link to resolve checkpatch warning.

Changes in v2:
- Changed to a single retry of 30ms based on previous feedback.

 drivers/input/rmi4/rmi_smbus.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/input/rmi4/rmi_smbus.c b/drivers/input/rmi4/rmi_smbus.c
index 4bf0e1df6a4a..b6d90c92e8a2 100644
--- a/drivers/input/rmi4/rmi_smbus.c
+++ b/drivers/input/rmi4/rmi_smbus.c
@@ -45,13 +45,25 @@ static int rmi_smb_get_version(struct rmi_smb_xport *rmi_smb)
 	int retval;
 
 	/* Check if for SMBus new version device by reading version byte. */
-	retval = i2c_smbus_read_byte_data(client, SMB_PROTOCOL_VERSION_ADDRESS);
-	if (retval < 0) {
+	for (int i = 0; i < 2; i++) {
+		if (i > 0) {
+			dev_warn(&client->dev, "sleeping to retry getting the SMBus version number\n");
+			fsleep(30000);
+		}
+		retval = i2c_smbus_read_byte_data(client,
+				SMB_PROTOCOL_VERSION_ADDRESS);
+		if (retval >= 0)
+			return retval + 1;
+
 		dev_err(&client->dev, "failed to get SMBus version number!\n");
-		return retval;
+		/* There can be a delay on resume where the read returns
+		 * -ENXIO. Retry to allow additional time for the read
+		 *  to become responsive.
+		 */
+		if (retval != -ENXIO)
+			break;
 	}
-
-	return retval + 1;
+	return retval;
 }
 
 /* SMB block write - wrapper over ic2_smb_write_block */
-- 
2.41.0.162.gfafddb0af9-goog

Re: [PATCH v3] Input: synaptics-rmi4 - retry reading SMBus version on resume

[kernel test robot]

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20230608210404.722123-1-jefferymiller@google.com>
References: <20230608210404.722123-1-jefferymiller@google.com>
TO: Jeffery Miller <jefferymiller@google.com>
TO: Dmitry Torokhov <dmitry.torokhov@gmail.com>
CC: Jonathan Denose <jdenose@chromium.org>
CC: jdenose@google.com
CC: Lyude Paul <lyude@redhat.com>
CC: benjamin.tissoires@redhat.com
CC: Andrew Duggan <andrew@duggan.us>
CC: loic.poulain@linaro.org
CC: Jeffery Miller <jefferymiller@google.com>
CC: Javier Martinez Canillas <javierm@redhat.com>
CC: Jeremy Kerr <jk@codeconstruct.com.au>
CC: Jonathan Cameron <Jonathan.Cameron@huawei.com>
CC: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
CC: linux-input@vger.kernel.org
CC: linux-kernel@vger.kernel.org

Hi Jeffery,

kernel test robot noticed the following build warnings:

[auto build test WARNING on dtor-input/next]
[also build test WARNING on dtor-input/for-linus linus/master v6.4-rc5 next-20230609]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jeffery-Miller/Input-synaptics-rmi4-retry-reading-SMBus-version-on-resume/20230609-050652
base:   https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git next
patch link:    https://lore.kernel.org/r/20230608210404.722123-1-jefferymiller%40google.com
patch subject: [PATCH v3] Input: synaptics-rmi4 - retry reading SMBus version on resume
:::::: branch date: 23 hours ago
:::::: commit date: 23 hours ago
config: arm64-randconfig-m031-20230608 (https://download.01.org/0day-ci/archive/20230610/202306100350.ck6PwGko-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 12.3.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202306100350.ck6PwGko-lkp@intel.com/

smatch warnings:
drivers/input/rmi4/rmi_smbus.c:66 rmi_smb_get_version() error: uninitialized symbol 'retval'.

vim +/retval +66 drivers/input/rmi4/rmi_smbus.c

82264d0cf7aef2 Benjamin Tissoires 2016-11-08  41  
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  42  static int rmi_smb_get_version(struct rmi_smb_xport *rmi_smb)
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  43  {
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  44  	struct i2c_client *client = rmi_smb->client;
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  45  	int retval;
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  46  
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  47  	/* Check if for SMBus new version device by reading version byte. */
0fe13a588e68ca Jeffery Miller     2023-06-08  48  	for (int i = 0; i < 2; i++) {
0fe13a588e68ca Jeffery Miller     2023-06-08  49  		if (i > 0) {
0fe13a588e68ca Jeffery Miller     2023-06-08  50  			dev_warn(&client->dev, "sleeping to retry getting the SMBus version number\n");
0fe13a588e68ca Jeffery Miller     2023-06-08  51  			fsleep(30000);
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  52  		}
0fe13a588e68ca Jeffery Miller     2023-06-08  53  		retval = i2c_smbus_read_byte_data(client,
0fe13a588e68ca Jeffery Miller     2023-06-08  54  				SMB_PROTOCOL_VERSION_ADDRESS);
0fe13a588e68ca Jeffery Miller     2023-06-08  55  		if (retval >= 0)
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  56  			return retval + 1;
0fe13a588e68ca Jeffery Miller     2023-06-08  57  
0fe13a588e68ca Jeffery Miller     2023-06-08  58  		dev_err(&client->dev, "failed to get SMBus version number!\n");
0fe13a588e68ca Jeffery Miller     2023-06-08  59  		/* There can be a delay on resume where the read returns
0fe13a588e68ca Jeffery Miller     2023-06-08  60  		 * -ENXIO. Retry to allow additional time for the read
0fe13a588e68ca Jeffery Miller     2023-06-08  61  		 *  to become responsive.
0fe13a588e68ca Jeffery Miller     2023-06-08  62  		 */
0fe13a588e68ca Jeffery Miller     2023-06-08  63  		if (retval != -ENXIO)
0fe13a588e68ca Jeffery Miller     2023-06-08  64  			break;
0fe13a588e68ca Jeffery Miller     2023-06-08  65  	}
0fe13a588e68ca Jeffery Miller     2023-06-08 @66  	return retval;
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  67  }
82264d0cf7aef2 Benjamin Tissoires 2016-11-08  68  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v3] Input: synaptics-rmi4 - retry reading SMBus version on resume

[Dmitry Torokhov]

Hi Jeffery,

On Thu, Jun 08, 2023 at 09:04:00PM +0000, Jeffery Miller wrote:
> On resume there can be a period of time after the
> preceding serio_resume -> psmouse_deactivate call
> where calls to rmi_smb_get_version fail with
> -ENXIO.
> 
> The call path in rmi_smb_resume is rmi_smb_resume -> rmi_smb_reset ->
> rmi_smb_enable_smbus_mode -> rmi_smb_get_version where
> this failure would occur.
> 
> Add a 30ms delay and retry in the ENXIO case to ensure the following
> rmi_driver_resume calls in rmi_smbus_resume can succeed.
> 
> This behavior was seen on a Lenovo T440p machine that required
> a delay of approximately 7-12ms.
> 
> The 30ms delay was chosen based on the linux-input message:
> Link: https://lore.kernel.org/all/BYAPR03MB47572F2C65E52ED673238D41B2439@BYAPR03MB4757.namprd03.prod.outlook.com/

I do not quite like putting these retries in RMI code. I wonder if we
should not move the delay into psmouse_smbus_reconnect():

	if (smbdev->need_deactivate) {
		psmouse_deactivate(psmouse);
		/* Give the device time to switch to SMBus mode */
		msleep(30);
	}

or even factor it out into psmouse_activate_smbus_mode() and call it
from psmouse_smbus_reconnect() as well as psmouse_smbus_init().

Thanks.

or even factor it out into psmouse_activate_smbus_mode() and call it
from psmouse_smbus_reconnect() as well as psmouse_smbus_init().

Thanks.

-- 
Dmitry