Attachment 45633 Details for Bug 36221 – better fix

[patch] better fix

0001-i2c-algo-bit-make-sure-to-call-pre-post_xfer-for-bit.patch (text/plain), 2.34 KB, created by Alex Deucher on 2011-04-14 14:03:58 UTC

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Creator: Alex Deucher

Created: 2011-04-14 14:03:58 UTC

Size: 2.34 KB

patch

obsolete

>From e6ef4d8a8177f9539c297e87da547dbe9ee10a26 Mon Sep 17 00:00:00 2001
>From: Alex Deucher <alexdeucher@gmail.com>
>Date: Thu, 14 Apr 2011 16:58:51 -0400
>Subject: [PATCH] i2c-algo-bit: make sure to call pre/post_xfer for bit_test
>
>Apparently some distros set i2c-algo-bit.bit_test to 1 by
>default.  In some cases this causes i2c_bit_add_bus
>to fail and prevents the i2c bus from being added.  In the
>radeon case, we fail to add the ddc i2c buses which prevents
>the driver from being able to detect attached monitors.
>The i2c bus works fine even if bit_test fails.  This is likely
>due to gpio switching that is required and handled in the
>pre/post_xfer hooks, so call the pre/post_xfer hooks in the
>bit test as well.
>
>Fixes:
>https://bugs.freedesktop.org/show_bug.cgi?id=36221
>
>Cc: Jean Delvare <khali@linux-fr.org>
>Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
>---
> drivers/i2c/algos/i2c-algo-bit.c |   21 ++++++++++++++++++---
> 1 files changed, 18 insertions(+), 3 deletions(-)
>
>diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
>index 38319a6..e2740e6 100644
>--- a/drivers/i2c/algos/i2c-algo-bit.c
>+++ b/drivers/i2c/algos/i2c-algo-bit.c
>@@ -232,9 +232,16 @@ static int i2c_inb(struct i2c_adapter *i2c_adap)
>  * Sanity check for the adapter hardware - check the reaction of
>  * the bus lines only if it seems to be idle.
>  */
>-static int test_bus(struct i2c_algo_bit_data *adap, char *name)
>+static int test_bus(struct i2c_adapter *i2c_adap, char *name)
> {
>-	int scl, sda;
>+	struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
>+	int scl, sda, ret;
>+
>+	if (adap->pre_xfer) {
>+		ret = adap->pre_xfer(i2c_adap);
>+		if (ret < 0)
>+			return -ENODEV;
>+	}
> 
> 	if (adap->getscl == NULL)
> 		pr_info("%s: Testing SDA only, SCL is not readable\n", name);
>@@ -297,11 +304,19 @@ static int test_bus(struct i2c_algo_bit_data *adap, char *name)
> 		       "while pulling SCL high!\n", name);
> 		goto bailout;
> 	}
>+
>+	if (adap->post_xfer)
>+		adap->post_xfer(i2c_adap);
>+
> 	pr_info("%s: Test OK\n", name);
> 	return 0;
> bailout:
> 	sdahi(adap);
> 	sclhi(adap);
>+
>+	if (adap->post_xfer)
>+		adap->post_xfer(i2c_adap);
>+
> 	return -ENODEV;
> }
> 
>@@ -607,7 +622,7 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap,
> 	int ret;
> 
> 	if (bit_test) {
>-		ret = test_bus(bit_adap, adap->name);
>+		ret = test_bus(adap, adap->name);
> 		if (ret < 0)
> 			return -ENODEV;
> 	}
>-- 
>1.7.1.1
>

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Attachments on bug 36221: 45589 | 45590 | 45615 | 45619 | 45633 | 45636 | 45637

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