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 <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
