On Tue, 1 May 2012, srinivas pandruvada wrote:
> When logical maximum is 0xffffffff, the parser fails even if
> logical minimum is equal to or greater than 0.
> By HID specification, if both the Logical Minimum and Logical
> Maximum extents are defined as positive values (0 or greater)
> then the report field can be assumed to be an unsigned value.
> Otherwise, all integer values are signed values represented
> in 2’s complement format.
Signed-off-by: line is missing, could you please fix that?
> ---
> drivers/hid/hid-core.c | 12 ++++++++++--
> 1 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index c757f10..b616f4b 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -225,8 +225,16 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign
> return -1;
> }
>
> - if (parser->global.logical_maximum < parser->global.logical_minimum) {
> - dbg_hid("logical range invalid %d %d\n", parser->global.logical_minimum, parser->global.logical_maximum);
> + if ((parser->global.logical_minimum < 0 &&
> + parser->global.logical_maximum <
> + parser->global.logical_minimum) ||
> + (parser->global.logical_minimum >= 0 &&
> + (__u32)parser->global.logical_maximum <
> + (__u32)parser->global.logical_minimum)
> + ) {
> + dbg_hid("logical range invalid 0x%x 0x%x\n",
> + parser->global.logical_minimum,
> + parser->global.logical_maximum);
> return -1;
> }
The change looks correct per se, but I will have to think a little bit
more whether other places of report parsing don't need similar adjustments
as well to work properly in such scenarios.
How did you find this out? By code/spec inspection, or do you actually
have the device that exposes this problem?
Thanks,
--
Jiri Kosina
SUSE Labs
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