From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3BC912BF01B; Mon, 16 Jun 2025 20:50:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750107058; cv=none; b=iTZMRSG0bOKtiv+4BWc3nNLSsZTspBFJi3l6iSO2FOi4XwWTF/0Ev2tkgGx+GLSyFKDWBTQ3IBB6m19UsxJNR06fjJce3IPR3Zm7A2WjdNiGN+Zu5ABuharwTG2BydjfPLpzoTnBCPyJFh1UaJPt5xktUSaXlB9oh+TVNDoGMag= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750107058; c=relaxed/simple; bh=ZwQBR3w6FYeENNK2A1rIxbwJvVKlbVENEpSzmjdyoL0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=gKAOlE+D+pmHv9hVNC5lkX7hMw7rVfS2SiwP8zF3osi5Cqnpa02YKEyPm18OxTmx9tMzkQ7Pucgr3XNWm1ccQBEf7ZvqcGPZ1qGQgveJjQ1dZ561Yvfy2BKipwn9YW4kzxN0r3M4fvDyCKKeDMCRCpu73nqZgddUyKOiVjuYs9M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E0ZSAZeX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="E0ZSAZeX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59E3AC4CEEA; Mon, 16 Jun 2025 20:50:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750107057; bh=ZwQBR3w6FYeENNK2A1rIxbwJvVKlbVENEpSzmjdyoL0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=E0ZSAZeXtEnI8R+5VVkK7FUknkYUVsTcXPlKs1sum/2uw/deaKdrqoBIb1lVDDMpM SXwSe58yy9H7RfcQUPhbCWpYF9haI6gLlfXVMJqRLkCNf9uwThjsSROxa71JWUk3MC u+BdsE8vs3ylrXY9jLgfwtHCUd2JdRdL9aU4cgH+kqiTqLah/A6R+LH4U4cH1LUb59 P+tj1ljW5yjJSw4xpsqAKFFGiOyF+DvJe6ahnpnbYjEoZW0IXe42pcSebpH3DYCeNs PstjLTaF+p7LSeodyPha9MCZHa/2mEoUTGd7RdG5+p9et2Md3kilsIdsOAKhIBo1as Cx52/T2T2rniA== Message-ID: <843b32df-64d5-4711-8415-4044174e575f@kernel.org> Date: Mon, 16 Jun 2025 22:50:54 +0200 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 5/5] media: uvcvideo: Use prio state from v4l2_device To: Ricardo Ribalda , Laurent Pinchart , Hans de Goede , Hans Verkuil , Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250616-uvc-fop-v4-0-250286570ee7@chromium.org> <20250616-uvc-fop-v4-5-250286570ee7@chromium.org> Content-Language: en-US, nl From: Hans de Goede In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Ricardo, On 16-Jun-25 8:30 PM, Ricardo Ribalda wrote: > Hello All > > On Mon, 16 Jun 2025 at 17:24, Ricardo Ribalda wrote: >> >> Currently, a UVC device can have multiple chains, and each chain maintains >> its own priority state. While this behavior is technically correct for UVC, >> uvcvideo is the *only* V4L2 driver that does not utilize the priority state >> defined within `v4l2_device`. >> >> This patch modifies uvcvideo to use the `v4l2_device` priority state. While >> this might not be strictly "correct" for uvcvideo's multi-chain design, it >> aligns uvcvideo with the rest of the V4L2 drivers, providing "correct enough" >> behavior and enabling code cleanup in v4l2-core. Also, multi-chain >> devices are extremely rare, they are typically implemented as two >> independent usb devices. > > As the cover letter says, this last patch 5/5 is a RFC. We can decide > if it is worth to keep it or not. > > The pros is that we can do some cleanup in the core, the cons is that > it might break kAPI. I've no objections against this change, but lets wait and see what Laurent has to say. Regards, Hans >> Signed-off-by: Ricardo Ribalda >> --- >> drivers/media/usb/uvc/uvc_driver.c | 2 -- >> drivers/media/usb/uvc/uvcvideo.h | 1 - >> 2 files changed, 3 deletions(-) >> >> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c >> index accfb4ca3c72cb899185ddc8ecf4e29143d58fc6..e3795e40f14dc325e5bd120f5f45b60937841641 100644 >> --- a/drivers/media/usb/uvc/uvc_driver.c >> +++ b/drivers/media/usb/uvc/uvc_driver.c >> @@ -1728,7 +1728,6 @@ static struct uvc_video_chain *uvc_alloc_chain(struct uvc_device *dev) >> INIT_LIST_HEAD(&chain->entities); >> mutex_init(&chain->ctrl_mutex); >> chain->dev = dev; >> - v4l2_prio_init(&chain->prio); >> >> return chain; >> } >> @@ -2008,7 +2007,6 @@ int uvc_register_video_device(struct uvc_device *dev, >> vdev->fops = fops; >> vdev->ioctl_ops = ioctl_ops; >> vdev->release = uvc_release; >> - vdev->prio = &stream->chain->prio; >> vdev->queue = &queue->queue; >> vdev->lock = &queue->mutex; >> if (type == V4L2_BUF_TYPE_VIDEO_OUTPUT) >> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h >> index 3e6d2d912f3a1cfcf63b2bc8edd3f86f3da305db..5ed9785d59c698cc7e0ac69955b892f932961617 100644 >> --- a/drivers/media/usb/uvc/uvcvideo.h >> +++ b/drivers/media/usb/uvc/uvcvideo.h >> @@ -354,7 +354,6 @@ struct uvc_video_chain { >> * uvc_fh.pending_async_ctrls >> */ >> >> - struct v4l2_prio_state prio; /* V4L2 priority state */ >> u32 caps; /* V4L2 chain-wide caps */ >> u8 ctrl_class_bitmap; /* Bitmap of valid classes */ >> }; >> >> -- >> 2.50.0.rc1.591.g9c95f17f64-goog >> > >