From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wm0-f66.google.com ([74.125.82.66]:33470 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751112AbdGNUOe (ORCPT ); Fri, 14 Jul 2017 16:14:34 -0400 Received: by mail-wm0-f66.google.com with SMTP id j85so12565600wmj.0 for ; Fri, 14 Jul 2017 13:14:34 -0700 (PDT) From: Philipp Zabel To: linux-media@vger.kernel.org Cc: Laurent Pinchart , Philipp Zabel Subject: [PATCH 1/3] [media] uvcvideo: variable size controls Date: Fri, 14 Jul 2017 22:14:22 +0200 Message-Id: <20170714201424.23592-1-philipp.zabel@gmail.com> Sender: linux-media-owner@vger.kernel.org List-ID: Some USB webcam controllers have extension unit controls that report different lengths via GET_LEN, depending on internal state. Add a flag to mark these controls as variable length and issue GET_LEN before GET/SET_CUR transfers to verify the current length. Signed-off-by: Philipp Zabel --- drivers/media/usb/uvc/uvc_ctrl.c | 26 +++++++++++++++++++++++++- include/uapi/linux/uvcvideo.h | 2 ++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c index c2ee6e39fd0c..ce69e2c6937d 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -1597,7 +1597,7 @@ static void uvc_ctrl_fixup_xu_info(struct uvc_device *dev, struct usb_device_id id; u8 entity; u8 selector; - u8 flags; + u16 flags; }; static const struct uvc_ctrl_fixup fixups[] = { @@ -1799,6 +1799,30 @@ int uvc_xu_ctrl_query(struct uvc_video_chain *chain, goto done; } + if ((ctrl->info.flags & UVC_CTRL_FLAG_VARIABLE_LEN) && reqflags) { + data = kmalloc(2, GFP_KERNEL); + /* Check if the control length has changed */ + ret = uvc_query_ctrl(chain->dev, UVC_GET_LEN, xqry->unit, + chain->dev->intfnum, xqry->selector, data, + 2); + size = le16_to_cpup((__le16 *)data); + kfree(data); + if (ret < 0) { + uvc_trace(UVC_TRACE_CONTROL, + "GET_LEN failed on control %pUl/%u (%d).\n", + entity->extension.guidExtensionCode, + xqry->selector, ret); + goto done; + } + if (ctrl->info.size != size) { + uvc_trace(UVC_TRACE_CONTROL, + "XU control %pUl/%u queried: len %u -> %u\n", + entity->extension.guidExtensionCode, + xqry->selector, ctrl->info.size, size); + ctrl->info.size = size; + } + } + if (size != xqry->size) { ret = -ENOBUFS; goto done; diff --git a/include/uapi/linux/uvcvideo.h b/include/uapi/linux/uvcvideo.h index 3b081862b9e8..0f0d63e79045 100644 --- a/include/uapi/linux/uvcvideo.h +++ b/include/uapi/linux/uvcvideo.h @@ -27,6 +27,8 @@ #define UVC_CTRL_FLAG_RESTORE (1 << 6) /* Control can be updated by the camera. */ #define UVC_CTRL_FLAG_AUTO_UPDATE (1 << 7) +/* Control can change LEN */ +#define UVC_CTRL_FLAG_VARIABLE_LEN (1 << 8) #define UVC_CTRL_FLAG_GET_RANGE \ (UVC_CTRL_FLAG_GET_CUR | UVC_CTRL_FLAG_GET_MIN | \ -- 2.13.2