Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935365AbdCLUKy (ORCPT ); Sun, 12 Mar 2017 16:10:54 -0400 Received: from hera.aquilenet.fr ([141.255.128.1]:38301 "EHLO hera.aquilenet.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934858AbdCLUKv (ORCPT ); Sun, 12 Mar 2017 16:10:51 -0400 Date: Sun, 12 Mar 2017 21:10:46 +0100 From: Samuel Thibault To: gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dave@mielke.cc, kevin.derome@epitech.eu, clause.andreabush@gmail.com, mengualjeanphi@free.fr Subject: [PATCH] usb-core: Add MS_INTR_BINTERVAL USB quirk Message-ID: <20170312201046.4jax6q5quugvpquh@var.youpi.perso.aquilenet.fr> Mail-Followup-To: Samuel Thibault , gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dave@mielke.cc, kevin.derome@epitech.eu, clause.andreabush@gmail.com, mengualjeanphi@free.fr MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Organization: I am not organized User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2145 Lines: 64 Some USB 2.0 devices erroneously report millisecond values in bInterval. The generic config code manages to catch most of them, but in some cases it's not completely enough. The case at stake here is a USB 2.0 braille device, which wants to announce 10ms and thus sets bInterval to 10, but with the USB 2.0 computation that yields to 64ms. It happens that one can type fast enough to reach this interval and get the device buffers overflown, leading to problematic latencies. The generic config code does not catch this case because the 64ms is considered a sane enough value. This change thus adds a USB_QUIRK_MS_INTR_BINTERVAL quirk to mark devices which actually report milliseconds in bInterval, and marks Vario Ultra devices as needing it. Signed-off-by: Samuel Thibault --- a/include/linux/usb/quirks.h +++ b/include/linux/usb/quirks.h @@ -50,4 +50,10 @@ /* device can't handle Link Power Management */ #define USB_QUIRK_NO_LPM BIT(10) +/* + * Device reports its bInterval as milliseconds instead of the + * USB 2.0 calculation. + */ +#define USB_QUIRK_MS_INTR_BINTERVAL BIT(11) + #endif /* __LINUX_USB_QUIRKS_H */ --- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -280,6 +280,14 @@ static int usb_parse_endpoint(struct dev /* * Adjust bInterval for quirked devices. + */ + /* + * This quirk fixes bIntervals reported in ms. + */ + if (to_usb_device(ddev)->quirks & + USB_QUIRK_MS_INTR_BINTERVAL) + i = j = n; + /* * This quirk fixes bIntervals reported in * linear microframes. */ --- a/drivers/usb/core/quirks.c +++ b/drivers/usb/core/quirks.c @@ -218,6 +218,14 @@ static const struct usb_device_id usb_qu /* INTEL VALUE SSD */ { USB_DEVICE(0x8086, 0xf1a5), .driver_info = USB_QUIRK_RESET_RESUME }, + /* Baum Vario Ultra */ + { USB_DEVICE(0x0904, 0x6101), .driver_info = + USB_QUIRK_MS_INTR_BINTERVAL }, + { USB_DEVICE(0x0904, 0x6102), .driver_info = + USB_QUIRK_MS_INTR_BINTERVAL }, + { USB_DEVICE(0x0904, 0x6103), .driver_info = + USB_QUIRK_MS_INTR_BINTERVAL }, + { } /* terminating entry must be last */ };