From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 D2AD317BB35; Tue, 13 Aug 2024 09:35:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723541752; cv=none; b=uID5+th/DH69hiKcBeYesDWMZTP/EJZLggJjuDivheTtosr1jhHpnBhlD176pBJ0qw356zlAR8lsIKTAv4DXY6CbMleuJWi1rsjcdTkHFwS92kROWvOtXeDq7LUIxL3xPHwRVCl4d+/p5xHDrd0F6JBaoU6rOJ2KQH1UX6WfJw4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723541752; c=relaxed/simple; bh=2fPJ4mZTRiTW1FkV/uqfRrVx7sxOLLvs4wZF1NDYsOY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cNhsbPTsmG6PEpndhvrAOu4dRI8avfWaAHrLCyPk2/KWvXGruSuknXNL2ayfNt7kHdgdu603ktnU1e50ppubWLYkwi44G2931N78KU4LOixv+caYBAXr5lQpu9j31cTVsPEy2dYruoB/goYx6kokes9bZz5rNsE5RweeNP33D84= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=vVQoBBM+; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="vVQoBBM+" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 586B6E4; Tue, 13 Aug 2024 11:34:52 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1723541692; bh=2fPJ4mZTRiTW1FkV/uqfRrVx7sxOLLvs4wZF1NDYsOY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=vVQoBBM+/txQtFLwSSf/Y02nVpZ2aAyHeSxA0Dx+Akeguhb9OsmAGUbZHGCzIVr7h 3ZCq/sIZNvbrvWvYYyf3XdNCM+k0Qkvx2MHTyzFEehKtIebCQywE1Ch/7eQ/7afG9x oiBKIDqAY99R3CIaEYQgEsV8id2/5bqeAkhAXP8w= Date: Tue, 13 Aug 2024 12:35:25 +0300 From: Laurent Pinchart To: Michael Grzeschik Cc: Daniel Scally , Greg Kroah-Hartman , Avichal Rakesh , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 10/10] usb: gadget: uvc: add min g_ctrl vidioc and set min buffs to 4 Message-ID: <20240813093525.GD19716@pendragon.ideasonboard.com> References: <20240403-uvc_request_length_by_interval-v4-0-ca22f334226e@pengutronix.de> <20240403-uvc_request_length_by_interval-v4-10-ca22f334226e@pengutronix.de> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240403-uvc_request_length_by_interval-v4-10-ca22f334226e@pengutronix.de> On Tue, Aug 13, 2024 at 11:09:34AM +0200, Michael Grzeschik wrote: > We increase the minimum amount of v4l2 buffers that will be possibly > enqueued into the hardware and allocate at least > UVCG_STREAMING_MIN_BUFFERS amount of requests. This way the driver has > also more requests available to prefill the isoc hardware with. > > Signed-off-by: Michael Grzeschik > > --- > v3 -> v4: - > v1 -> v3: new patch > --- > drivers/usb/gadget/function/uvc.h | 2 ++ > drivers/usb/gadget/function/uvc_queue.c | 3 ++- > drivers/usb/gadget/function/uvc_v4l2.c | 13 +++++++++++++ > 3 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h > index f6bc58fb02b84..e0b1f78fdbc65 100644 > --- a/drivers/usb/gadget/function/uvc.h > +++ b/drivers/usb/gadget/function/uvc.h > @@ -71,6 +71,8 @@ extern unsigned int uvc_gadget_trace_param; > > #define UVCG_REQUEST_HEADER_LEN 12 > > +#define UVCG_STREAMING_MIN_BUFFERS 4 > + 4 is a large number that drastically increases latency. > /* ------------------------------------------------------------------------ > * Structures > */ > diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c > index e33ce72325031..157e7f7d49c7a 100644 > --- a/drivers/usb/gadget/function/uvc_queue.c > +++ b/drivers/usb/gadget/function/uvc_queue.c > @@ -21,6 +21,7 @@ > #include > > #include "uvc.h" > +#include "uvc_video.h" > > /* ------------------------------------------------------------------------ > * Video buffers queue management. > @@ -86,7 +87,7 @@ static int uvc_queue_setup(struct vb2_queue *vq, > } > > video->req_size = req_size; > - video->uvc_num_requests = nreq; > + video->uvc_num_requests = nreq * UVCG_STREAMING_MIN_BUFFERS; > > return 0; > } > diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c > index 392fb400aad14..f96074f2c2824 100644 > --- a/drivers/usb/gadget/function/uvc_v4l2.c > +++ b/drivers/usb/gadget/function/uvc_v4l2.c > @@ -357,6 +357,18 @@ static int uvc_v4l2_s_parm(struct file *file, void *fh, > return 0; > } > > +static int uvc_g_ctrl(struct file *file, void *priv, struct v4l2_control *vc) > +{ > + int ret = -EINVAL; > + > + if (vc->id == V4L2_CID_MIN_BUFFERS_FOR_OUTPUT) { > + vc->value = UVCG_STREAMING_MIN_BUFFERS; > + ret = 0; > + } > + > + return ret; > +} > + > static int > uvc_v4l2_enum_frameintervals(struct file *file, void *fh, > struct v4l2_frmivalenum *fival) > @@ -629,6 +641,7 @@ const struct v4l2_ioctl_ops uvc_v4l2_ioctl_ops = { > .vidioc_streamoff = uvc_v4l2_streamoff, > .vidioc_s_parm = uvc_v4l2_s_parm, > .vidioc_g_parm = uvc_v4l2_g_parm, > + .vidioc_g_ctrl = uvc_g_ctrl, > .vidioc_subscribe_event = uvc_v4l2_subscribe_event, > .vidioc_unsubscribe_event = uvc_v4l2_unsubscribe_event, > .vidioc_default = uvc_v4l2_ioctl_default, -- Regards, Laurent Pinchart