[3.8.y.z extended stable] Patch "drm/radeon/atom: fix bus probes when hw_i2c is set (v2)" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    drm/radeon/atom: fix bus probes when hw_i2c is set (v2)

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 602133215050b2df6881072d1e3c12791f9d4a47 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher at amd.com>
Date: Tue, 3 Dec 2013 17:16:49 -0500
Subject: drm/radeon/atom: fix bus probes when hw_i2c is set (v2)

commit ffd3d3361d583cb73fa65a5fed3a196ba6f261bb upstream.

When probing the bus, we need to set the byte count
to 0 rather than 1.

v2: Don't count the first byte.

bug:
https://bugzilla.kernel.org/show_bug.cgi?id=66241

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
[ kamal: backport to 3.8 (context) ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/gpu/drm/radeon/atombios_i2c.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/radeon/atombios_i2c.c b/drivers/gpu/drm/radeon/atombios_i2c.c
index 4bb4b7a..1dfafb1 100644
--- a/drivers/gpu/drm/radeon/atombios_i2c.c
+++ b/drivers/gpu/drm/radeon/atombios_i2c.c
@@ -44,7 +44,7 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
 	PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
 	int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
 	unsigned char *base;
-	u16 out;
+	u16 out = cpu_to_le16(0);

 	memset(&args, 0, sizeof(args));

@@ -55,10 +55,14 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
 			DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 2)\n", num);
 			return -EINVAL;
 		}
-		if (num > 1) {
+		if (buf == NULL)
+			args.ucRegIndex = 0;
+		else
+			args.ucRegIndex = buf[0];
+		if (num)
 			num--;
+		if (num)
 			memcpy(&out, &buf[1], num);
-		}
 		args.lpI2CDataOut = cpu_to_le16(out);
 	} else {
 		if (num > ATOM_MAX_HW_I2C_READ) {
@@ -93,14 +97,14 @@ int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
 	struct radeon_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
 	struct i2c_msg *p;
 	int i, remaining, current_count, buffer_offset, max_bytes, ret;
-	u8 buf = 0, flags;
+	u8 flags;

 	/* check for bus probe */
 	p = &msgs[0];
 	if ((num == 1) && (p->len == 0)) {
 		ret = radeon_process_i2c_ch(i2c,
 					    p->addr, HW_I2C_WRITE,
-					    &buf, 1);
+					    NULL, 0);
 		if (ret)
 			return ret;
 		else
--
1.8.3.2