From mboxrd@z Thu Jan 1 00:00:00 1970 From: Loic Domaigne Subject: RFC: [PATCH 1/3] usb: cdc_ncm: patch for VMware Date: Fri, 8 Mar 2013 22:03:19 +0100 Message-ID: <20130308210319.GA4794@feynman.loic.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-usb@vger.kernel.org To: netdev@vger.kernel.org Return-path: Received: from mail-bk0-f54.google.com ([209.85.214.54]:45154 "EHLO mail-bk0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932528Ab3CHVDX (ORCPT ); Fri, 8 Mar 2013 16:03:23 -0500 Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: This patch limits the Rx URB size to 16kB if the driver is compiled for a VMware environment. As of workstation 9, there are some major performance problems if the Rx URB size exceeds that limit. This patch applies to longterm kernel version 3.4.35. Signed-Off-By: Loic Domaigne --- linux-3.4.35/drivers/net/usb/cdc_ncm.c.orig 2013-03-05 09:36:02.858740489 +0100 +++ linux-3.4.35/drivers/net/usb/cdc_ncm.c 2013-03-05 10:20:18.092588668 +0100 @@ -80,6 +80,23 @@ #define CDC_NCM_TIMER_PENDING_CNT 2 #define CDC_NCM_TIMER_INTERVAL (400UL * NSEC_PER_USEC) +/* maximum Rx URB size */ +/* + * in the original Linux driver, the rx urb size can be up to + * CDC_NCM_NTB_MAX_SIZE_RX. + * + * Under VMware (as of wks9), URB size greater than 16kB is a problem, + * so simply adjust this define when the driver is compiled for a VMware + * environment. + * + */ +#ifdef VMWARE_BUG +#warning "Compiling for VMware" +#define CDC_NCM_MAX_RX_URB_SIZE 16384 +#else +#define CDC_NCM_MAX_RX_URB_SIZE CDC_NCM_NTB_MAX_SIZE_RX +#endif + /* The following macro defines the minimum header space */ #define CDC_NCM_MIN_HDR_SIZE \ (sizeof(struct usb_cdc_ncm_nth16) + sizeof(struct usb_cdc_ncm_ndp16) + \ @@ -589,6 +606,9 @@ advance: ctx->out_ep->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK); dev->status = ctx->status_ep; dev->rx_urb_size = ctx->rx_max; + if (dev->rx_urb_size > CDC_NCM_MAX_RX_URB_SIZE) + dev->rx_urb_size = CDC_NCM_MAX_RX_URB_SIZE; + pr_debug("dev->rx_urb_size = %zu", dev->rx_urb_size); /* * We should get an event when network connection is "connected" or