From 8e7a1dbc7b0ae048bf3f4b9707fe1a845e69aab7 Mon Sep 17 00:00:00 2001 From: Guennadi Liakhovetski Date: Tue, 8 May 2018 11:07:44 -0400 Subject: [PATCH] media: uvcvideo: Handle control pipe protocol STALLs When a command ends up in a STALL on the control pipe, use the Request Error Code control to provide a more precise error information to the user. For example, if a camera is still busy processing a control, when the same or an interrelated control set request arrives, the camera can react with a STALL and then return the "Not ready" status in response to a UVC_VC_REQUEST_ERROR_CODE_CONTROL command. With this patch the user would then get an EBUSY error code instead of a generic EPIPE. Signed-off-by: Guennadi Liakhovetski Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/uvc/uvc_video.c | 52 ++++++++++++++++++++++++++++++++++----- 1 file changed, 46 insertions(+), 6 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index 3ed5f27..86a99f4 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -73,17 +73,57 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, u8 intfnum, u8 cs, void *data, u16 size) { int ret; + u8 error; + u8 tmp; ret = __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size, UVC_CTRL_CONTROL_TIMEOUT); - if (ret != size) { - uvc_printk(KERN_ERR, "Failed to query (%s) UVC control %u on " - "unit %u: %d (exp. %u).\n", uvc_query_name(query), cs, - unit, ret, size); - return -EIO; + if (likely(ret == size)) + return 0; + + uvc_printk(KERN_ERR, + "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n", + uvc_query_name(query), cs, unit, ret, size); + + if (ret != -EPIPE) + return ret; + + tmp = *(u8 *)data; + + ret = __uvc_query_ctrl(dev, UVC_GET_CUR, 0, intfnum, + UVC_VC_REQUEST_ERROR_CODE_CONTROL, data, 1, + UVC_CTRL_CONTROL_TIMEOUT); + + error = *(u8 *)data; + *(u8 *)data = tmp; + + if (ret != 1) + return ret < 0 ? ret : -EPIPE; + + uvc_trace(UVC_TRACE_CONTROL, "Control error %u\n", error); + + switch (error) { + case 0: + /* Cannot happen - we received a STALL */ + return -EPIPE; + case 1: /* Not ready */ + return -EBUSY; + case 2: /* Wrong state */ + return -EILSEQ; + case 3: /* Power */ + return -EREMOTE; + case 4: /* Out of range */ + return -ERANGE; + case 5: /* Invalid unit */ + case 6: /* Invalid control */ + case 7: /* Invalid Request */ + case 8: /* Invalid value within range */ + return -EINVAL; + default: /* reserved or unknown */ + break; } - return 0; + return -EPIPE; } static void uvc_fixup_video_ctrl(struct uvc_streaming *stream, -- 2.7.4