Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751393AbaLPOwa (ORCPT ); Tue, 16 Dec 2014 09:52:30 -0500 Received: from lekensteyn.nl ([178.21.112.251]:43068 "EHLO lekensteyn.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751363AbaLPOw3 (ORCPT ); Tue, 16 Dec 2014 09:52:29 -0500 From: Peter Wu To: Benjamin Tissoires Cc: Jiri Kosina , Nestor Lopez Casado , linux-input , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/3] HID: logitech-hidpp: detect HID++ 2.0 errors too Date: Tue, 16 Dec 2014 15:52:23 +0100 Message-ID: <1973926.ykacZQ6J6W@al> User-Agent: KMail/4.14.3 (Linux/3.17.0-rc4-custom-00168-g7ec62d4; KDE/4.14.3; x86_64; ; ) In-Reply-To: References: <1418691016-30681-1-git-send-email-peter@lekensteyn.nl> <1418691016-30681-2-git-send-email-peter@lekensteyn.nl> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Spam-Score: 0.0 (/) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 16 December 2014 09:33:44 Benjamin Tissoires wrote: > On Mon, Dec 15, 2014 at 7:50 PM, Peter Wu wrote: > > Devices speaking HID++ 2.0 report a different error code (0xff). Detect > > these errors too to avoid 5 second delays when the device reports an > > error. Caught by... well, a bug in the QEMU emulation of this receiver. > > > > Renamed fap to rap for HID++ 1.0 errors because it is more logical, > > it has no functional difference. > > > > Signed-off-by: Peter Wu > > --- > > I'd like to have Nestor's opinion on this. I did not manage to find on > the documentation that HID++ 2.0 Long report error code is 0xff, so > introducing this change without Logitech's blessing would be > unfortunate. > I understand this will fix your qemu problem, but I am not entirely > sure if we do not have to check on 0xff and 0x8f in both short and > long responses. > > Cheers, > Benjamin The error code was found by probing the hardware. The HID++ 2.0 spec does define some error codes, for example an OutOfRange error when GetFeatureID is called with a featureIndex greater than the available features count. The documentation also defines the valid FeatureIndex range as 1..254, so I thought it was reasonable to assume that 0xff is the HID++ 2.0 error indicator. Nestor, so far I have only seen the OutOfRange error when the arguments are invalid. Are there other cases where HID++ 2.0 are reported instead of HID++ 1.0? QEMU was not the problem though, it was just a bug in my usb-ltunify-receiver device emulation which exposed this missing check. Kind regards, Peter > > drivers/hid/hid-logitech-hidpp.c | 17 ++++++++++++++--- > > 1 file changed, 14 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c > > index 2f420c0..ae23dec 100644 > > --- a/drivers/hid/hid-logitech-hidpp.c > > +++ b/drivers/hid/hid-logitech-hidpp.c > > @@ -105,6 +105,7 @@ struct hidpp_device { > > }; > > > > > > +/* HID++ 1.0 error codes */ > > #define HIDPP_ERROR 0x8f > > #define HIDPP_ERROR_SUCCESS 0x00 > > #define HIDPP_ERROR_INVALID_SUBID 0x01 > > @@ -119,6 +120,8 @@ struct hidpp_device { > > #define HIDPP_ERROR_REQUEST_UNAVAILABLE 0x0a > > #define HIDPP_ERROR_INVALID_PARAM_VALUE 0x0b > > #define HIDPP_ERROR_WRONG_PIN_CODE 0x0c > > +/* HID++ 2.0 error codes */ > > +#define HIDPP20_ERROR 0xff > > > > static void hidpp_connect_event(struct hidpp_device *hidpp_dev); > > > > @@ -192,9 +195,16 @@ static int hidpp_send_message_sync(struct hidpp_device *hidpp, > > } > > > > if (response->report_id == REPORT_ID_HIDPP_SHORT && > > - response->fap.feature_index == HIDPP_ERROR) { > > + response->rap.sub_id == HIDPP_ERROR) { > > + ret = response->rap.params[1]; > > + dbg_hid("%s:got hidpp error %02X\n", __func__, ret); > > + goto exit; > > + } > > + > > + if (response->report_id == REPORT_ID_HIDPP_LONG && > > + response->fap.feature_index == HIDPP20_ERROR) { > > ret = response->fap.params[1]; > > - dbg_hid("__hidpp_send_report got hidpp error %02X\n", ret); > > + dbg_hid("%s:got hidpp 2.0 error %02X\n", __func__, ret); > > goto exit; > > } > > > > @@ -271,7 +281,8 @@ static inline bool hidpp_match_answer(struct hidpp_report *question, > > static inline bool hidpp_match_error(struct hidpp_report *question, > > struct hidpp_report *answer) > > { > > - return (answer->fap.feature_index == HIDPP_ERROR) && > > + return ((answer->rap.sub_id == HIDPP_ERROR) || > > + (answer->fap.feature_index == HIDPP20_ERROR)) && > > (answer->fap.funcindex_clientid == question->fap.feature_index) && > > (answer->fap.params[0] == question->fap.funcindex_clientid); > > } > > -- > > 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/