radeon/i2c: do not count reg index in number of i2c byte we are writing.

Useless to count the register index in number of bytes we are writing.

Fixes a regression with hw i2c enabled.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/radeon/atombios_i2c.c b/drivers/gpu/drm/radeon/atombios_i2c.c
index deaf98c..0652ee0 100644 (file)
--- a/drivers/gpu/drm/radeon/atombios_i2c.c
+++ b/drivers/gpu/drm/radeon/atombios_i2c.c
@@ -56,8 +56,10 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
                        return -EINVAL;
                }
                args.ucRegIndex = buf[0];
-               if (num > 1)
-                       memcpy(&out, &buf[1], num - 1);
+               if (num > 1) {
+                       num--;
+                       memcpy(&out, &buf[1], num);
+               }
                args.lpI2CDataOut = cpu_to_le16(out);
        } else {
                if (num > ATOM_MAX_HW_I2C_READ) {