From: Jiri Kosina Date: Sat, 10 Mar 2007 21:45:45 +0000 (+0100) Subject: HID: zeroing of bytes in output fields is bogus X-Git-Tag: v2.6.21-rc4~4^2 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d108d4fe34730135647fe32a4f8091491d3542ea;p=linux-2.6 HID: zeroing of bytes in output fields is bogus This patch removes bogus zeroing of unused bits in output reports, introduced in Simon's patch in commit d4ae650a. According to the specification, any sane device should not care about values of unused bits. What is worse, the zeroing is done in a way which is broken and might clear certain bits in output reports which are actually _used_ - a device that has multiple fields with one value of the size 1 bit each might serve as an example of why this is bogus - the second call of hid_output_report() would clear the first bit of report, which has already been set up previously. This patch will break LEDs on SpaceNavigator, because this device is broken and takes into account the bits which it shouldn't touch. The quirk for this particular device will be provided in a separate patch. Signed-off-by: Jiri Kosina --- diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index e5894a75a6..d28d76d220 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -875,10 +875,6 @@ static void hid_output_field(struct hid_field *field, __u8 *data) unsigned size = field->report_size; unsigned n; - /* make sure the unused bits in the last byte are zeros */ - if (count > 0 && size > 0) - data[(offset+count*size-1)/8] = 0; - for (n = 0; n < count; n++) { if (field->logical_minimum < 0) /* signed values */ implement(data, offset + n * size, size, s32ton(field->value[n], size));