Re: [PATCH] HID: multitouch: Fetch feature reports on demand for Win8 devices

[Jiri Kosina]

On Wed, 30 Sep 2015, Mika Westerberg wrote:

> > I would be in favor of applying the patch in its current shape, but if
> > Jiri thinks we need a little bit more caution here, we would need to add
> > a test regarding the Win8 capability here.
> 
> What about adding following on top of this patch? It checks the device
> in question belongs to "win8 class".
> 
> I can send a new version of the patch if this seems reasonable.

If this actually maintains the backwards compatibility for that particular 
device Benjamin mentioned (no idea what mtclass does it have?), I'd be in 
favor of doing that.

Thanks,

-- 
Jiri Kosina
SUSE Labs

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Re: [PATCH] HID: multitouch: Fetch feature reports on demand for Win8 devices

[Mika Westerberg]

On Tue, Sep 29, 2015 at 05:04:31AM -0400, Benjamin Tissoires wrote:
> > +static void mt_get_feature(struct hid_device *hdev, struct hid_report 
> > *report)
> > +{
> > +   int ret, size = hid_report_len(report);
> > +   u8 *buf;
> > +
> > +   /*
> > +* Only fetch the feature report if initial reports are not already
> > +* been retrieved. Currently this is only done for Windows 8 touch
> > +* devices.
> > +*/
> > +   if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS))
> > +   return;
> 
> Some Win 7 panels have this quirk set too because they do not support
> either querying random feature or input reports.
> 
> I think this test is safe given that this is, I think, what the Windows
> driver does (I remember that it queries for the features it needs).
> However I am not 100% sure if this will not break one low quality
> touchscreen.
> 
> I would be in favor of applying the patch in its current shape, but if
> Jiri thinks we need a little bit more caution here, we would need to add
> a test regarding the Win8 capability here.

What about adding following on top of this patch? It checks the device
in question belongs to "win8 class".

I can send a new version of the patch if this seems reasonable.

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index d9ca2b96ab68..72c55a3f650f 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -311,6 +311,7 @@ static struct attribute_group mt_attribute_group = {
 
 static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
 {
+   struct mt_device *td = hid_get_drvdata(hdev);
int ret, size = hid_report_len(report);
u8 *buf;
 
@@ -319,7 +320,8 @@ static void mt_get_feature(struct hid_device *hdev, struct 
hid_report *report)
 * been retrieved. Currently this is only done for Windows 8 touch
 * devices.
 */
-   if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS))
+   if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS) ||
+   td->mtclass.name != MT_CLS_WIN_8)
return;
 
buf = hid_alloc_report_buf(report, GFP_KERNEL);
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Re: [PATCH] HID: multitouch: Fetch feature reports on demand for Win8 devices

[Benjamin Tissoires]

On Sep 28 2015 or thereabouts, Mika Westerberg wrote:
> Some newer Intel Skylake based Dell laptops with Win8 precision touchpad
> fail when initial feature reports are fetched from it. Below is an example
> output with some additional debug included:
> 
>  i2c_hid i2c-DLL0704:01: Fetching the HID descriptor
>  i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=20 00
>  i2c_hid i2c-DLL0704:01: HID Descriptor: 1e 00 00 01 99 02 21 00 24 ...
>  ...
>  i2c_hid i2c-DLL0704:01: i2c_hid_get_report
>  i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 38 02 23 00
>  i2c_hid i2c-DLL0704:01: report (len=4): 04 00 08 05
>  i2c_hid i2c-DLL0704:01: report id 13
>  i2c_hid i2c-DLL0704:01: i2c_hid_get_report
>  i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 3d 02 23 00
>  i2c_hid i2c-DLL0704:01: failed to retrieve report from device.
>  i2c_hid i2c-DLL0704:01: report id 7
>  i2c_hid i2c-DLL0704:01: i2c_hid_get_report
>  i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 37 02 23 00
>  i2c_hid i2c-DLL0704:01: report (len=259): 03 01 07 fc 28 fe 84 40 ...
>  i2c_hid i2c-DLL0704:01: report id 4
>  i2c_hid i2c-DLL0704:01: i2c_hid_get_report
>  i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 34 02 23 00
> 
> We manage to fetch few reports but then the touchpad dies:
> 
>  i2c_designware i2c_designware.1: i2c_dw_handle_tx_abort: lost arbitration
>  i2c_hid i2c-DLL0704:01: failed to retrieve report from device.
> 
> it eventually pulls the whole I2C bus low:
> 
>  i2c_designware i2c_designware.1: controller timed out
>  i2c_hid i2c-DLL0704:01: failed to set a report to device.
> 
> Fix this by preventing initial feature report retrieval for Win8 devices.
> Instead we fetch reports as needed in mt_feature_mapping(). This prevents
> fetching reports which might cause problems with the device in question.
> 
> Suggested-by: Benjamin Tissoires 
> Signed-off-by: Mika Westerberg 
> ---
> This is a second version. The first one which just prevented initial report
> reading can be found here:
> 
>   https://lkml.org/lkml/2015/9/24/191
> 
> This version tries to do what Benjamin suggested by reading feature values
> as needed in mt_feature_mapping(). This fixes the issue in the Dell laptop
> I have here.

Thanks for the re-spin Mika.

I just have one comment that needs discussion:

> 
>  drivers/hid/hid-multitouch.c | 42 +-
>  1 file changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index 661b4fce1a5d..d9ca2b96ab68 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -309,6 +309,38 @@ static struct attribute_group mt_attribute_group = {
>   .attrs = sysfs_attrs
>  };
>  
> +static void mt_get_feature(struct hid_device *hdev, struct hid_report 
> *report)
> +{
> + int ret, size = hid_report_len(report);
> + u8 *buf;
> +
> + /*
> +  * Only fetch the feature report if initial reports are not already
> +  * been retrieved. Currently this is only done for Windows 8 touch
> +  * devices.
> +  */
> + if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS))
> + return;

Some Win 7 panels have this quirk set too because they do not support
either querying random feature or input reports.

I think this test is safe given that this is, I think, what the Windows
driver does (I remember that it queries for the features it needs).
However I am not 100% sure if this will not break one low quality
touchscreen.

I would be in favor of applying the patch in its current shape, but if
Jiri thinks we need a little bit more caution here, we would need to add
a test regarding the Win8 capability here.

Jiri?

If we apply it, this patch is:
Reviewed-by: Benjamin Tissoires 

Cheers,
Benjamin

> +
> + buf = hid_alloc_report_buf(report, GFP_KERNEL);
> + if (!buf)
> + return;
> +
> + ret = hid_hw_raw_request(hdev, report->id, buf, size,
> +  HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
> + if (ret < 0) {
> + dev_warn(>dev, "failed to fetch feature %d\n",
> +  report->id);
> + } else {
> + ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, buf,
> +size, 0);
> + if (ret)
> + dev_warn(>dev, "failed to report feature\n");
> + }
> +
> + kfree(buf);
> +}
> +
>  static void mt_feature_mapping(struct hid_device *hdev,
>   struct hid_field *field, struct hid_usage *usage)
>  {
> @@ -327,6 +359,8 @@ static void mt_feature_mapping(struct hid_device *hdev,
>  
>   break;
>   case HID_DG_CONTACTMAX:
> + mt_get_feature(hdev, field->report);
> +
>   td->maxcontact_report_id = field->report->id;
>   td->maxcontacts = field->value[0];
>   if 

[PATCH] HID: multitouch: Fetch feature reports on demand for Win8 devices

[Mika Westerberg]

Some newer Intel Skylake based Dell laptops with Win8 precision touchpad
fail when initial feature reports are fetched from it. Below is an example
output with some additional debug included:

 i2c_hid i2c-DLL0704:01: Fetching the HID descriptor
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=20 00
 i2c_hid i2c-DLL0704:01: HID Descriptor: 1e 00 00 01 99 02 21 00 24 ...
 ...
 i2c_hid i2c-DLL0704:01: i2c_hid_get_report
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 38 02 23 00
 i2c_hid i2c-DLL0704:01: report (len=4): 04 00 08 05
 i2c_hid i2c-DLL0704:01: report id 13
 i2c_hid i2c-DLL0704:01: i2c_hid_get_report
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 3d 02 23 00
 i2c_hid i2c-DLL0704:01: failed to retrieve report from device.
 i2c_hid i2c-DLL0704:01: report id 7
 i2c_hid i2c-DLL0704:01: i2c_hid_get_report
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 37 02 23 00
 i2c_hid i2c-DLL0704:01: report (len=259): 03 01 07 fc 28 fe 84 40 ...
 i2c_hid i2c-DLL0704:01: report id 4
 i2c_hid i2c-DLL0704:01: i2c_hid_get_report
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 34 02 23 00

We manage to fetch few reports but then the touchpad dies:

 i2c_designware i2c_designware.1: i2c_dw_handle_tx_abort: lost arbitration
 i2c_hid i2c-DLL0704:01: failed to retrieve report from device.

it eventually pulls the whole I2C bus low:

 i2c_designware i2c_designware.1: controller timed out
 i2c_hid i2c-DLL0704:01: failed to set a report to device.

Fix this by preventing initial feature report retrieval for Win8 devices.
Instead we fetch reports as needed in mt_feature_mapping(). This prevents
fetching reports which might cause problems with the device in question.

Suggested-by: Benjamin Tissoires 
Signed-off-by: Mika Westerberg 
---
This is a second version. The first one which just prevented initial report
reading can be found here:

  https://lkml.org/lkml/2015/9/24/191

This version tries to do what Benjamin suggested by reading feature values
as needed in mt_feature_mapping(). This fixes the issue in the Dell laptop
I have here.

 drivers/hid/hid-multitouch.c | 42 +-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 661b4fce1a5d..d9ca2b96ab68 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -309,6 +309,38 @@ static struct attribute_group mt_attribute_group = {
.attrs = sysfs_attrs
 };
 
+static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
+{
+   int ret, size = hid_report_len(report);
+   u8 *buf;
+
+   /*
+* Only fetch the feature report if initial reports are not already
+* been retrieved. Currently this is only done for Windows 8 touch
+* devices.
+*/
+   if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS))
+   return;
+
+   buf = hid_alloc_report_buf(report, GFP_KERNEL);
+   if (!buf)
+   return;
+
+   ret = hid_hw_raw_request(hdev, report->id, buf, size,
+HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
+   if (ret < 0) {
+   dev_warn(>dev, "failed to fetch feature %d\n",
+report->id);
+   } else {
+   ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, buf,
+  size, 0);
+   if (ret)
+   dev_warn(>dev, "failed to report feature\n");
+   }
+
+   kfree(buf);
+}
+
 static void mt_feature_mapping(struct hid_device *hdev,
struct hid_field *field, struct hid_usage *usage)
 {
@@ -327,6 +359,8 @@ static void mt_feature_mapping(struct hid_device *hdev,
 
break;
case HID_DG_CONTACTMAX:
+   mt_get_feature(hdev, field->report);
+
td->maxcontact_report_id = field->report->id;
td->maxcontacts = field->value[0];
if (!td->maxcontacts &&
@@ -343,6 +377,7 @@ static void mt_feature_mapping(struct hid_device *hdev,
break;
}
 
+   mt_get_feature(hdev, field->report);
if (field->value[usage->usage_index] == MT_BUTTONTYPE_CLICKPAD)
td->is_buttonpad = true;
 
@@ -1029,8 +1064,13 @@ static int mt_probe(struct hid_device *hdev, const 
struct hid_device_id *id)
 * reports. Fortunately, the Win8 spec says that all touches
 * should be sent during each report, making the initialization
 * of input reports unnecessary.
+*
+* In addition some touchpads do not behave well if we read
+* all feature reports from them. Instead we prevent
+* initial report fetching and then selectively fetch each
+* report we are interested in.