diff mbox

Zeroing the report before setting fields

Message ID 20100304143349.2d861ec6@redhat.com
State New, archived
Headers show

Commit Message

Pete Zaitcev March 4, 2010, 9:33 p.m. UTC
None
diff mbox

Patch

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index eabe5f8..14b45b1 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -929,6 +929,15 @@  exit:
 	kfree(value);
 }
 
+static unsigned int hid_field_length(struct hid_field *field)
+{
+	unsigned count = field->report_count;
+	unsigned offset = field->report_offset;
+	unsigned size = field->report_size;
+
+	return offset + count * size;
+}
+
 /*
  * Output the field into the report.
  */
@@ -938,13 +947,8 @@  static void hid_output_field(struct hid_field *field, __u8 *data)
 	unsigned count = field->report_count;
 	unsigned offset = field->report_offset;
 	unsigned size = field->report_size;
-	unsigned bitsused = offset + count * size;
 	unsigned n;
 
-	/* make sure the unused bits in the last byte are zeros */
-	if (count > 0 && size > 0 && (bitsused % 8) != 0)
-		data[(bitsused-1)/8] &= (1 << (bitsused % 8)) - 1;
-
 	for (n = 0; n < count; n++) {
 		if (field->logical_minimum < 0)	/* signed values */
 			implement(data, offset + n * size, size, s32ton(field->value[n], size));
@@ -960,10 +964,19 @@  static void hid_output_field(struct hid_field *field, __u8 *data)
 void hid_output_report(struct hid_report *report, __u8 *data)
 {
 	unsigned n;
+	unsigned length, bitsused;
 
 	if (report->id > 0)
 		*data++ = report->id;
 
+	length = 0;
+	for (n = 0; n < report->maxfield; n++) {
+		bitsused = hid_field_length(report->field[n]);
+		if (bitsused > length)
+			length = bitsused;
+	}
+	memset(data, 0, (length + 7) / 8);
+
 	for (n = 0; n < report->maxfield; n++)
 		hid_output_field(report->field[n], data);
 }