On 03/19/2013 10:38 PM, Henrik Rydberg wrote:

Hi Benjamin,

quoted

This is not just cosmetics, it can help to write udev and X.org
rules.

Signed-off-by: Benjamin Tissoires <redacted>
---
 drivers/hid/hid-multitouch.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index d89f0eb..faeec95 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c

@@ -44,6 +44,7 @@
 #include <linux/slab.h>
 #include <linux/usb.h>
 #include <linux/input/mt.h>
+#include <linux/string.h>
 
 
 MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");

@@ -371,6 +372,15 @@ static int mt_pen_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 		unsigned long **bit, int *max)
 {
 	struct mt_device *td = hid_get_drvdata(hdev);
+	char *name;
+
+	if (hi->input->name == hdev->name) {
+		name = kzalloc(sizeof(hdev->name) + 5, GFP_KERNEL);
+		if (name) {
+			sprintf(name, "%s Pen", hdev->name);
+			hi->input->name = name;
+		}
+	}

Why not simply duplicate the the string? This kind of magic sharing is
not really helping.  Also, for multi input devices, the assumptions in
hidinput_allocate() seem to be the culprit. Perhaps the fix should be
there instead.

Yes, hidinput_allocate() clearly steals the reference here. However,
fixing this in hid-core would not be simpler: some drivers (ntrig does
at least) assume that there is no need to free input->name, which means
that:
- either we need to fix each individual driver
- either we introduce some kind of mechanism in order not to free "const
char *" declarations like it happens in ntrig.

In v2, I'll just realloc for each input the input->name, and then if the
pen is here, then it will realloc the new name.

Cheers,
Benjamin

quoted

 
 	td->pen_report_id = field->report->id;
 

@@ -914,6 +924,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	int ret, i;
 	struct mt_device *td;
 	struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */
+	struct hid_input *hi;
 
 	for (i = 0; mt_classes[i].name ; i++) {
 		if (id->driver_data == mt_classes[i].name) {

@@ -964,7 +975,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 	if (ret)
-		goto fail;
+		goto hid_fail;
 
 	ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);
 

@@ -976,6 +987,10 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	return 0;
 
+hid_fail:
+	list_for_each_entry(hi, &hdev->inputs, list)
+		if (hi->input->name != hdev->name)
+			kfree(hi->input->name);
 fail:
 	kfree(td->fields);
 	kfree(td);

@@ -1020,8 +1035,15 @@ static int mt_resume(struct hid_device *hdev)
 static void mt_remove(struct hid_device *hdev)
 {
 	struct mt_device *td = hid_get_drvdata(hdev);
+	struct hid_input *hi;
+
 	sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
 	hid_hw_stop(hdev);
+
+	list_for_each_entry(hi, &hdev->inputs, list)
+		if (hi->input->name != hdev->name)
+			kfree(hi->input->name);
+
 	kfree(td);
 	hid_set_drvdata(hdev, NULL);
 }

-- 
1.8.1.2

Thanks,
Henrik