From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Ricardo Ribalda <ribalda@chromium.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 01/12] media: uvcvideo: Fix race condition handling events
Date: Tue, 22 Dec 2020 10:04:32 +0200 [thread overview]
Message-ID: <X+GokHQbUHcquCnm@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20201221164819.792019-2-ribalda@chromium.org>
Hi Ricardo,
Thank you for the patch.
On Mon, Dec 21, 2020 at 05:48:08PM +0100, Ricardo Ribalda wrote:
> The control and its data needs to be copied to the workqueue at the same
> time to avoid half-updates of the events.
> This is, events reported to userspace were the control id does not match
> its value.
Actually, after discussing this with you on IRC, I'm not sure there's a
problem. The URB is resubmitted by uvc_ctrl_status_event_work(), so the
data shouldn't be overwritten before it is processed.
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 2 +-
> drivers/media/usb/uvc/uvcvideo.h | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 011e69427b7c..aa18dcdf8165 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1332,7 +1332,7 @@ bool uvc_ctrl_status_event(struct urb *urb, struct uvc_video_chain *chain,
> return false;
> }
>
> - w->data = data;
> + memcpy(w->data, data, ctrl->info.size);
> w->urb = urb;
> w->chain = chain;
> w->ctrl = ctrl;
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index a3dfacf069c4..0db6c2e0bd98 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -678,7 +678,7 @@ struct uvc_device {
> struct urb *urb;
> struct uvc_video_chain *chain;
> struct uvc_control *ctrl;
> - const void *data;
> + u8 data[UVC_MAX_STATUS_SIZE];
> } async_ctrl;
> };
>
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2020-12-22 8:05 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-21 16:48 [PATCH v5 00/12]Show privacy_gpio as a v4l2_ctrl Ricardo Ribalda
2020-12-21 16:48 ` [PATCH v5 01/12] media: uvcvideo: Fix race condition handling events Ricardo Ribalda
2020-12-22 8:04 ` Laurent Pinchart [this message]
2020-12-21 16:48 ` [PATCH v5 02/12] media: uvcvideo: Allow more that one asyc_ctrl Ricardo Ribalda
2020-12-22 8:07 ` Laurent Pinchart
2020-12-21 16:48 ` [PATCH v5 03/12] media: uvcvideo: Move guid to entity Ricardo Ribalda
2020-12-21 16:48 ` [PATCH v5 04/12] media: uvcvideo: Allow extra entities Ricardo Ribalda
2020-12-21 18:17 ` Ricardo Ribalda
2020-12-21 16:48 ` [PATCH v5 05/12] media: uvcvideo: Allow entities with no pads Ricardo Ribalda
2020-12-21 16:48 ` [PATCH v5 06/12] media: uvcvideo: Allow entity-defined get_info and get_cur Ricardo Ribalda
2020-12-21 16:48 ` [PATCH v5 07/12] media: uvcvideo: Implement UVC_EXT_GPIO_UNIT Ricardo Ribalda
2020-12-22 8:33 ` Laurent Pinchart
2020-12-22 8:37 ` Laurent Pinchart
2020-12-22 18:36 ` Ricardo Ribalda
2020-12-23 7:54 ` Laurent Pinchart
2020-12-21 16:48 ` [PATCH v5 08/12] media: uvcvideo: Add Privacy control based on EXT_GPIO Ricardo Ribalda
2020-12-21 16:48 ` [PATCH v5 09/12] media: uvcvideo: Implement UVC_QUIRK_PRIVACY_DURING_STREAM Ricardo Ribalda
2020-12-22 10:29 ` Laurent Pinchart
2020-12-22 20:04 ` Ricardo Ribalda
2020-12-23 8:04 ` Laurent Pinchart
2020-12-23 8:31 ` Ricardo Ribalda
2020-12-23 12:55 ` Ricardo Ribalda
2021-04-20 4:54 ` Tomasz Figa
2022-02-04 5:59 ` Tomasz Figa
2020-12-21 16:48 ` [PATCH v5 10/12] media: uvcvideo: Use dev_ printk aliases Ricardo Ribalda
2020-12-21 16:48 ` [PATCH v5 11/12] media: uvcvideo: New macro uvc_trace_cont Ricardo Ribalda
2020-12-21 16:48 ` [PATCH v5 12/12] media: uvcvideo: use dev_dbg() for uvc_trace() Ricardo Ribalda
2020-12-22 8:51 ` Laurent Pinchart
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