On Sun, 5 Aug 2012, Marek Vasut wrote:
> The Freescale i.MX28 BootROM USB recovery mode implements the USB HID
> protocol, yet the global item tag report size is 128. Linux checks if
> this is 96 as of now, see [1]. This causes Linux to refuse to communicate
> with this device, making it impossible to use the recovery mode.
>
> This is not a standard HID device per se, but rather a software emulation
> implemented within the BootROM code and realized through USB OTG-capable
> port switched to device mode present on the device.
>
> Previous attempt to discuss this issue dates back to 2011, see [2]. There
> has been not much response. Also noteworthy is the [3], where there seems
> to be a pointing device that has issue similar to this one.
>
> The tool making use of the USB recovery mode is available at [4].
>
> [1] http://comments.gmane.org/gmane.linux.kernel.input/22328
> [2] http://www.spinics.net/lists/linux-usb/msg43463.html
> [3] https://bbs.archlinux.org/viewtopic.php?pid=1141340
> [4] http://git.bfuser.eu/?p=marex/mxsldr.git;a=summary
>
> Signed-off-by: Marek Vasut <ma...@denx.de>
> Cc: Chen Peter <b29...@freescale.com>
> Cc: Greg KH <g...@kroah.com>
> Cc: Jiri Kosina <jkos...@suse.cz>
I have not admit I don't remember where the original limit came from --
the spec doesn't mandate it as far as I can tell.
I am queueing this patch now for next merge window. Thanks.
> ---
> drivers/hid/hid-core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 60ea284..2b9dd76 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -374,7 +374,7 @@ static int hid_parser_global(struct hid_parser *parser,
> struct hid_item *item)
>
> case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
> parser->global.report_size = item_udata(item);
> - if (parser->global.report_size > 96) {
> + if (parser->global.report_size > 128) {
> hid_err(parser->device, "invalid report_size %d\n",
> parser->global.report_size);
> return -1;
> --
> 1.7.10.4
>
--
Jiri Kosina
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
