diff options
Diffstat (limited to 'meta/recipes-kernel/linux/linux-omap2-git/beagleboard/i2c-omap-race-fix.diff')
| -rw-r--r-- | meta/recipes-kernel/linux/linux-omap2-git/beagleboard/i2c-omap-race-fix.diff | 118 |
1 files changed, 0 insertions, 118 deletions
diff --git a/meta/recipes-kernel/linux/linux-omap2-git/beagleboard/i2c-omap-race-fix.diff b/meta/recipes-kernel/linux/linux-omap2-git/beagleboard/i2c-omap-race-fix.diff deleted file mode 100644 index 6eb33f76b..000000000 --- a/meta/recipes-kernel/linux/linux-omap2-git/beagleboard/i2c-omap-race-fix.diff +++ /dev/null @@ -1,118 +0,0 @@ -From linux-omap-owner@vger.kernel.org Tue Jul 15 21:23:13 2008 -Received: from localhost - ([127.0.0.1] helo=dominion ident=koen) - by dominion.dominion.void with esmtp (Exim 4.69) - (envelope-from <linux-omap-owner@vger.kernel.org>) - id 1KIq7E-0004FX-VS - for koen@localhost; Tue, 15 Jul 2008 21:23:13 +0200 -Received: from xs.service.utwente.nl [130.89.5.250] - by dominion with POP3 (fetchmail-6.3.6) - for <koen@localhost> (single-drop); Tue, 15 Jul 2008 21:23:12 +0200 (CEST) -Received: from mail.service.utwente.nl ([130.89.5.254]) by exchange.service.utwente.nl with Microsoft SMTPSVC(6.0.3790.3959); - Tue, 15 Jul 2008 21:01:02 +0200 -Received: from mx.utwente.nl ([130.89.2.12]) by mail.service.utwente.nl with Microsoft SMTPSVC(6.0.3790.3959); - Tue, 15 Jul 2008 21:01:01 +0200 -Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) - by mx.utwente.nl (8.12.10/SuSE Linux 0.7) with ESMTP id m6FJ0qDf031889 - for <k.kooi@student.utwente.nl>; Tue, 15 Jul 2008 21:00:52 +0200 -Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand - id S1756776AbYGOTAV (ORCPT <rfc822;k.kooi@student.utwente.nl>); - Tue, 15 Jul 2008 15:00:21 -0400 -Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755065AbYGOTAV - (ORCPT <rfc822;linux-omap-outgoing>); - Tue, 15 Jul 2008 15:00:21 -0400 -Received: from utopia.booyaka.com ([72.9.107.138]:35569 "EHLO - utopia.booyaka.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org - with ESMTP id S1756776AbYGOTAU (ORCPT - <rfc822;linux-omap@vger.kernel.org>); Tue, 15 Jul 2008 15:00:20 -0400 -Received: (qmail 2982 invoked by uid 526); 15 Jul 2008 19:00:18 -0000 -Date: Tue, 15 Jul 2008 13:00:18 -0600 (MDT) -From: Paul Walmsley <paul@pwsan.com> -To: linux-omap@vger.kernel.org -Subject: [PATCH] i2c-omap: close suspected race between omap_i2c_idle() and - omap_i2c_isr() -Message-ID: <alpine.DEB.1.00.0807151259180.467@utopia.booyaka.com> -User-Agent: Alpine 1.00 (DEB 882 2007-12-20) -MIME-Version: 1.0 -Content-Type: TEXT/PLAIN; charset=US-ASCII -Sender: linux-omap-owner@vger.kernel.org -Precedence: bulk -List-ID: <linux-omap.vger.kernel.org> -X-Mailing-List: linux-omap@vger.kernel.org -X-UTwente-MailScanner-Information: Scanned by MailScanner. Contact servicedesk@icts.utwente.nl for more information. -X-UTwente-MailScanner: Found to be clean -X-UTwente-MailScanner-From: linux-omap-owner@vger.kernel.org -X-Spam-Status: No -X-OriginalArrivalTime: 15 Jul 2008 19:01:01.0610 (UTC) FILETIME=[1FBA68A0:01C8E6AD] - - -omap_i2c_idle() sets an internal flag, "dev->idle", instructing its -ISR to decline interrupts. It sets this flag before it actually masks -the interrupts on the I2C controller. This is problematic, since an -I2C interrupt could arrive after dev->idle is set, but before the -interrupt source is masked. When this happens, Linux disables the I2C -controller's IRQ, causing all future transactions on the bus to fail. - -Symptoms, happening on about 7% of boots: - - irq 56: nobody cared (try booting with the "irqpoll" option) - <warning traceback here> - Disabling IRQ #56 - i2c_omap i2c_omap.1: controller timed out - -In omap_i2c_idle(), this patch sets dev->idle only after the interrupt -mask write to the I2C controller has left the ARM write buffer. -That's probably the major offender. For additional prophylaxis, in -omap_i2c_unidle(), the patch clears the dev->idle flag before -interrupts are enabled, rather than afterwards. - -The patch has survived twenty-two reboots on the 3430SDP here without -wedging I2C1. Not absolutely dispositive, but promising! - - -Signed-off-by: Paul Walmsley <paul@pwsan.com> ---- - - drivers/i2c/busses/i2c-omap.c | 10 ++++++++-- - 1 files changed, 8 insertions(+), 2 deletions(-) - -diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c -index 55779f5..ed7e9ad 100644 ---- a/drivers/i2c/busses/i2c-omap.c -+++ b/drivers/i2c/busses/i2c-omap.c -@@ -209,22 +209,28 @@ static void omap_i2c_unidle(struct omap_i2c_dev *dev) - if (dev->iclk != NULL) - clk_enable(dev->iclk); - clk_enable(dev->fclk); -+ dev->idle = 0; - if (dev->iestate) - omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate); -- dev->idle = 0; - } - - static void omap_i2c_idle(struct omap_i2c_dev *dev) - { - u16 iv; - -- dev->idle = 1; - dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG); - omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0); - if (dev->rev1) - iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); - else - omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate); -+ /* -+ * The wmb() is to ensure that the I2C interrupt mask write -+ * reaches the I2C controller before the dev->idle store -+ * occurs. -+ */ -+ wmb(); -+ dev->idle = 1; - clk_disable(dev->fclk); - if (dev->iclk != NULL) - clk_disable(dev->iclk); --- -To unsubscribe from this list: send the line "unsubscribe linux-omap" in -the body of a message to majordomo@vger.kernel.org -More majordomo info at http://vger.kernel.org/majordomo-info.html - |