Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941391AbcJGR0z (ORCPT ); Fri, 7 Oct 2016 13:26:55 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:46798 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938971AbcJGRYr (ORCPT ); Fri, 7 Oct 2016 13:24:47 -0400 From: Mauro Carvalho Chehab To: Linux Media Mailing List Cc: Mauro Carvalho Chehab , Mauro Carvalho Chehab , Andy Lutomirski , Johannes Stezenbach , Jiri Kosina , Patrick Boettcher , Linux Kernel Mailing List , Andy Lutomirski , Michael Krufky , Mauro Carvalho Chehab , =?UTF-8?q?J=C3=B6rg=20Otte?= , Julia Lawall , Hans Verkuil Subject: [PATCH 22/26] technisat-usb2: use DMA buffers for I2C transfers Date: Fri, 7 Oct 2016 14:24:32 -0300 Message-Id: <2792fc0fbd2bb0366c6967c60184c93fecc828c3.1475860773.git.mchehab@s-opensource.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2036 Lines: 72 The USB control messages require DMA to work. We cannot pass a stack-allocated buffer, as it is not warranted that the stack would be into a DMA enabled area. On this driver, most of the transfers are OK, but the I2C one was using stack. Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/dvb-usb/technisat-usb2.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/media/usb/dvb-usb/technisat-usb2.c b/drivers/media/usb/dvb-usb/technisat-usb2.c index d9f3262bf071..4706628a3ed5 100644 --- a/drivers/media/usb/dvb-usb/technisat-usb2.c +++ b/drivers/media/usb/dvb-usb/technisat-usb2.c @@ -89,9 +89,13 @@ struct technisat_usb2_state { static int technisat_usb2_i2c_access(struct usb_device *udev, u8 device_addr, u8 *tx, u8 txlen, u8 *rx, u8 rxlen) { - u8 b[64]; + u8 *b; int ret, actual_length; + b = kmalloc(64, GFP_KERNEL); + if (!b) + return -ENOMEM; + deb_i2c("i2c-access: %02x, tx: ", device_addr); debug_dump(tx, txlen, deb_i2c); deb_i2c(" "); @@ -123,7 +127,7 @@ static int technisat_usb2_i2c_access(struct usb_device *udev, if (ret < 0) { err("i2c-error: out failed %02x = %d", device_addr, ret); - return -ENODEV; + goto err; } ret = usb_bulk_msg(udev, @@ -131,7 +135,7 @@ static int technisat_usb2_i2c_access(struct usb_device *udev, b, 64, &actual_length, 1000); if (ret < 0) { err("i2c-error: in failed %02x = %d", device_addr, ret); - return -ENODEV; + goto err; } if (b[0] != I2C_STATUS_OK) { @@ -140,7 +144,7 @@ static int technisat_usb2_i2c_access(struct usb_device *udev, if (!(b[0] == I2C_STATUS_NAK && device_addr == 0x60 /* && device_is_technisat_usb2 */)) - return -ENODEV; + goto err; } deb_i2c("status: %d, ", b[0]); @@ -154,7 +158,9 @@ static int technisat_usb2_i2c_access(struct usb_device *udev, deb_i2c("\n"); - return 0; +err: + kfree(b); + return ret; } static int technisat_usb2_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, -- 2.7.4