From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Subject: re: Input: atmel_mxt_ts - read and report bootloader version Date: Wed, 21 May 2014 15:26:24 +0300 Message-ID: <20140521122624.GB23396@mwanda> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:18532 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751202AbaEUM0c (ORCPT ); Wed, 21 May 2014 08:26:32 -0400 Content-Disposition: inline Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: nick.dyer@itdev.co.uk Cc: linux-input@vger.kernel.org Hello Nick Dyer, The patch e57a66aa8534: "Input: atmel_mxt_ts - read and report bootloader version" from May 18, 2014, leads to the following static checker warning: drivers/input/touchscreen/atmel_mxt_ts.c:437 mxt_get_bootloader_version() warn: signedness bug returning '(-5)' drivers/input/touchscreen/atmel_mxt_ts.c 429 static u8 mxt_get_bootloader_version(struct mxt_data *data, u8 val) 430 { 431 struct device *dev = &data->client->dev; 432 u8 buf[3]; 433 434 if (val & MXT_BOOT_EXTENDED_ID) { 435 if (mxt_bootloader_read(data, &buf[0], 3) != 0) { 436 dev_err(dev, "%s: i2c failure\n", __func__); 437 return -EIO; ^^^^ This gets truncated into a number from 0-255 and anyway the caller doesn't check for errors. 438 } 439 440 dev_dbg(dev, "Bootloader ID:%d Version:%d\n", buf[1], buf[2]); 441 442 return buf[0]; 443 } else { 444 dev_dbg(dev, "Bootloader ID:%d\n", val & MXT_BOOT_ID_MASK); 445 446 return val; 447 } 448 } regards, dan carpenter