From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A03DBC433DB for ; Tue, 23 Mar 2021 15:26:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6571561992 for ; Tue, 23 Mar 2021 15:26:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232747AbhCWPZn (ORCPT ); Tue, 23 Mar 2021 11:25:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232578AbhCWPZi (ORCPT ); Tue, 23 Mar 2021 11:25:38 -0400 Received: from mail-lf1-x133.google.com (mail-lf1-x133.google.com [IPv6:2a00:1450:4864:20::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F0CAFC061574 for ; Tue, 23 Mar 2021 08:25:37 -0700 (PDT) Received: by mail-lf1-x133.google.com with SMTP id m12so27217481lfq.10 for ; Tue, 23 Mar 2021 08:25:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=92a1gsExe+NbSoH43J0S+ebb5eR/4sS4gTC5JOKWQWU=; b=JOZqaJyyk3SQsn8d14eUPoz/8BV/S8ZdH0DmyQ2vvT5CA3XIc5/dDVe0REx+nGckP1 rInh+AHdw07XVDNDm6eeoPgHuH3eOOTLLjRoP8SqHrFKH90mCu3Uj/E0MLvQH3M5RX+6 TLxhsZj76z5HhrXXYNi6i8W1luDIDOTyyKQRdr7WQDWKenN0GrDj1qNGMY2VhiCK0wbt 6DnULwhjtqgnM9H0QtRugPf5c14UDQIMldZGtsENyjtwS80rp84WeZYsdyc7uyto1/fn FLlqG2HKDr7ZfRnE8JOjKvaLqtpaofjkIG3CTZxUKPiclQuGn5tdZIoy9qCNuQk9wuZB AREw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=92a1gsExe+NbSoH43J0S+ebb5eR/4sS4gTC5JOKWQWU=; b=lK0+tIZXogPnbczzUEk+RGRlO/DBmsm3XidDqEvGIU5gqIiF0ZW8iB5dRwL727uT9v Vc3srKheooly5gb1SIDjpIx9Fbx4B8ZAgcPwji59xIq4wC5ers85vaVU1BgddBXGucDr GyeSUfAG56NPC64VtcbhFXGLbIoJ9ZRZ3soedv+f1L22lNaj03jiBFsz6ngyDWLQVpP/ jfHZRdWZboTVj+slk+pbfVmWjR+K75Y0r+/PA8kXZ8TFrD2OOu45fnTmgXfJH3BTx0Tz Ocd/mIidZdm8sr9zd1r0A3gH19TXndNfRNspB1GsHTl2ZkUJ8gfSFbq90kHuRIWev6Wc 0dNg== X-Gm-Message-State: AOAM533T64vfzfzNMI18dH+LJPYOvi5AiMYKrpJymXQWttWC+8oRsHX4 ptw1euf4skibQmlhUw4M/8amPbsUxk+vu1SLJ/3hzd9gAhiqkw== X-Google-Smtp-Source: ABdhPJwQa+6E7O4/6+TsmeDx7uKkMjfoxuC3F2vFIT03PRqm5y0TIEDnVPcngZDKkqvqEibhUujMPbgJy+leZoWj25Q= X-Received: by 2002:a19:434a:: with SMTP id m10mr2829552lfj.2.1616513136057; Tue, 23 Mar 2021 08:25:36 -0700 (PDT) MIME-Version: 1.0 References: <347cdb4a-19a2-98ce-580f-5aba4abfb2fc@xs4all.nl> In-Reply-To: <347cdb4a-19a2-98ce-580f-5aba4abfb2fc@xs4all.nl> From: Ricardo Ribalda Delgado Date: Tue, 23 Mar 2021 16:25:20 +0100 Message-ID: Subject: Re: [PATCH] uvcvideo: improve error handling in uvc_query_ctrl() To: Hans Verkuil Cc: Ricardo Ribalda , Linux Media Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Hans Thanks for the patch. I like how uvc is ending :) On Mon, Mar 22, 2021 at 1:09 PM Hans Verkuil wrote: > > - If __uvc_query_ctrl() failed with a non-EPIPE error, then > report that with dev_err. If an error code is obtained, then > report that with dev_dbg. > > - For error 2 (Wrong state) return -EACCES instead of -EILSEQ. > EACCES is a much more appropriate error code. EILSEQ will return > "Invalid or incomplete multibyte or wide character." in strerror(), > which is a *very* confusing message. > > Signed-off-by: Hans Verkuil > --- > Ricardo, this too can be added to the uvc series. > --- > drivers/media/usb/uvc/uvc_video.c | 44 +++++++++++++++++-------------- > 1 file changed, 24 insertions(+), 20 deletions(-) > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c > index b63c073ec30e..3f461bb4eeb9 100644 > --- a/drivers/media/usb/uvc/uvc_video.c > +++ b/drivers/media/usb/uvc/uvc_video.c > @@ -68,7 +68,7 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, > u8 intfnum, u8 cs, void *data, u16 size) > { > int ret; > - u8 error; > + u8 error = 0; > u8 tmp; > > ret = __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size, > @@ -76,35 +76,39 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, > if (likely(ret == size)) > return 0; > > - dev_dbg(&dev->udev->dev, > - "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n", > - uvc_query_name(query), cs, unit, ret, size); > + ret = ret < 0 ? ret : -EPIPE; > > - if (ret != -EPIPE) > - return ret; > - > - tmp = *(u8 *)data; > + if (ret == -EPIPE) { > + tmp = *(u8 *)data; > > - ret = __uvc_query_ctrl(dev, UVC_GET_CUR, 0, intfnum, > - UVC_VC_REQUEST_ERROR_CODE_CONTROL, data, 1, > - UVC_CTRL_CONTROL_TIMEOUT); > + ret = __uvc_query_ctrl(dev, UVC_GET_CUR, 0, intfnum, > + UVC_VC_REQUEST_ERROR_CODE_CONTROL, data, 1, > + UVC_CTRL_CONTROL_TIMEOUT); > > - error = *(u8 *)data; > - *(u8 *)data = tmp; > + if (ret == 1) > + error = *(u8 *)data; > + *(u8 *)data = tmp; > + if (ret != 1) > + ret = ret < 0 ? ret : -EPIPE; > + } > > - if (ret != 1) > - return ret < 0 ? ret : -EPIPE; > + if (error) > + dev_dbg(&dev->udev->dev, > + "Failed to query (%s) UVC control %u on unit %u: got error %u.\n", > + uvc_query_name(query), cs, unit, error); > + else > + dev_err(&dev->udev->dev, > + "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n", > + uvc_query_name(query), cs, unit, ret, size); If __uvc_query_ctrl and UVC_VC_REQUEST_ERROR_CODE_CONTROL failed, error is 0. And I think that you want to show a dev_err in that case. Maybe we can initialize error to 7 ? > > - uvc_dbg(dev, CONTROL, "Control error %u\n", error); > + if (!error) > + return ret; I think we do not want these two lines (read next comment) > > switch (error) { > - case 0: > - /* Cannot happen - we received a STALL */ > - return -EPIPE; > case 1: /* Not ready */ > return -EBUSY; > case 2: /* Wrong state */ > - return -EILSEQ; > + return -EACCES; > case 3: /* Power */ > return -EREMOTE; > case 4: /* Out of range */ Maybe we want a dev_dbg if the error code is unknown and return ret? > -- > 2.30.0 > -- Ricardo Ribalda