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 082FCC47094 for ; Mon, 7 Jun 2021 20:19:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D0F7C610A2 for ; Mon, 7 Jun 2021 20:19:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231263AbhFGUU7 (ORCPT ); Mon, 7 Jun 2021 16:20:59 -0400 Received: from mail-lj1-f182.google.com ([209.85.208.182]:39707 "EHLO mail-lj1-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230502AbhFGUU7 (ORCPT ); Mon, 7 Jun 2021 16:20:59 -0400 Received: by mail-lj1-f182.google.com with SMTP id c11so23942923ljd.6 for ; Mon, 07 Jun 2021 13:18:52 -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=aVD8lq1uNANeZKWp0ZPkE9JXADJnLuidcBKbXh2dcbI=; b=Bv1Pt/sAx0q2PDSnmNa0pGYRgEyRTbhZO5Zmb99/9IvWZxsicenBbsIaT4QeU0SE8Y 41Ab/+s5z1Lon0v7c34t3H0SNH5Xu6kF3TKNZI3AWAGBaAbBwPdC8tUwQhimimY+vHks DA7AjLy6eRbBDzvQZRwoBNmxF2CSYVEatbDPkD99QS9L2tKQcrZPqXTDqnXPZ6gM+1X4 uYY/hdsNaDsCMcKiVrFEQscpeCPXY/+8OUvzwnhYnzhYscra1lnFY/sBYSlm/h1AqO1i VsWURb4NbccZ+2hOD/x1cF1JoBee+e+Bvw12ElTKM0lloTRBaof4wAU/JnXakQqtIQLa nPDQ== 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=aVD8lq1uNANeZKWp0ZPkE9JXADJnLuidcBKbXh2dcbI=; b=ZIBkDrV3/M3YlpipU17eHx8IBveq3qrt3QFB1wWYxwuNHYjsN+/97pNerONkjCAJ+H w41N3xwzX/TG5SE2P54AzsO59jARA4GWwDg7GG6/Ov5pmyVvCG3r65BRgC/u00DPC8lR SHYnBIp75tlqtIqQ8ulZ7yYPqporvEGlhUh/ffB73sQ1gH8Fc28vrXo2C+9echL+7U7q 5hwRF0zckonvoe1gEZH39V6MDyAJmcC+I9jbLIUI6o5t4mIyIyy9Ik8MMMYiD+r4bFrY mf5jR1MB1niQ8etyRiKIFep/wfcKfE7gjoLHxCYs4Iz8W46ke0wkhdIYXT032EKxIZ/h xBqw== X-Gm-Message-State: AOAM533e3sYy7Rc1MJkJvxCw1aQWE2rXf2acI9nisgmYrbRrcWA4Q3++ AuqGk9jyfec3KEY7dSM2nb4q36YU1q4WQBKsgmgoqtA3Ya0= X-Google-Smtp-Source: ABdhPJw0/qPxUNO5vXTaB06yRHt8+85C/oalaRbTTgF25himPKRudMcaDKldQ9WXAPwVsbnZuFE0N3PJqcVVn5yNDHE= X-Received: by 2002:a2e:9e53:: with SMTP id g19mr16475855ljk.58.1623097071585; Mon, 07 Jun 2021 13:17:51 -0700 (PDT) MIME-Version: 1.0 References: <478e73fc-0e2c-4f1b-11d4-c71067764571@selasky.org> In-Reply-To: From: Ricardo Ribalda Delgado Date: Mon, 7 Jun 2021 22:17:35 +0200 Message-ID: Subject: Re: [PATCH] Genesys Logic UVC microscopes used to work with Linux To: Hans Petter Selasky , Laurent Pinchart Cc: Linux Media Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Maybe you want to handle this with a quirk? I suspect that some devices might work differently with this patches? On Sun, Jun 6, 2021 at 3:36 PM Hans Petter Selasky wrote: > > Hi, > > Some USB video class compliant devices, like Genesys Logic camera chips, > used in cheap microscopes, doesn't provide any image if there are UVC > SET current value commands for the processing unit, before the camera > stream is activated. Fix this by not issuing any UVC SET current value > commands, if the value was not changed. This should also work fine with > existing UVC compliant webcams and optimized the number of needed > processing unit control endpoint requests. > > Signed-off-by: Hans Petter Selasky > > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c > b/drivers/media/usb/uvc/uvc_ctrl.c > index b3dde98499f4..0d7137eca331 100644 > --- a/drivers/media/usb/uvc/uvc_ctrl.c > +++ b/drivers/media/usb/uvc/uvc_ctrl.c > @@ -1697,7 +1697,13 @@ int uvc_ctrl_set(struct uvc_fh *handle, > if (ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS) > ctrl->handle = handle; > > - ctrl->dirty = 1; > + /* Avoid setting the current value. */ > + if (!ctrl->dirty && > + memcmp(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_BACKUP), > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT), > + ctrl->info.size) != 0) > + ctrl->dirty = 1; > + > ctrl->modified = 1; > return 0; > } -- Ricardo Ribalda