Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751404AbdLZCz2 (ORCPT ); Mon, 25 Dec 2017 21:55:28 -0500 Received: from szxga01-in.huawei.com ([45.249.212.187]:2433 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750888AbdLZCz0 (ORCPT ); Mon, 25 Dec 2017 21:55:26 -0500 From: Lipengcheng To: "balbi@kernel.org" CC: "gregkh@linuxfoundation.org" , "linux-kernel@vger.kernel.org" , "linux-usb@vger.kernel.org" , Lipengcheng Subject: [PATCH] usb: gadget: uvc:change the UVC_NUM_REQUESTS value Thread-Topic: [PATCH] usb: gadget: uvc:change the UVC_NUM_REQUESTS value Thread-Index: AQHTfebEU9xEaystOEuj8doRCalYCg== Date: Tue, 26 Dec 2017 02:52:08 +0000 Message-ID: <637796ED17F7774FB27D6AAE3C6951584B38D3F6@dggeml508-mbx.china.huawei.com> Accept-Language: zh-CN, en-US Content-Language: zh-CN X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.67.222.17] Content-Type: text/plain; charset="utf-8" Content-ID: MIME-Version: 1.0 X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id vBQ2tZAu005742 Content-Length: 844 Lines: 26 The value is 4, it can cache four descriptors. When streaming_interval = 1, it can tolerate 500us. Some busy scenes, it may be more than 500us because cpu scheduling is not timely. There will have some problems. It is better set to eight. Signed-off-by: Pengcheng Li --- drivers/usb/gadget/function/uvc.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h index a64e07e..901487e 100644 --- a/drivers/usb/gadget/function/uvc.h +++ b/drivers/usb/gadget/function/uvc.h @@ -90,7 +90,7 @@ extern unsigned int uvc_gadget_trace_param; * Driver specific constants */ -#define UVC_NUM_REQUESTS 4 +#define UVC_NUM_REQUESTS 8 #define UVC_MAX_REQUEST_SIZE 64 #define UVC_MAX_EVENTS 4 -- 2.7.4