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

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/atombios_i2c.c b/drivers/gpu/drm/radeon/atombios_i2c.c
index deaf98cdca3a..0652ee0a2098 100644
--- 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) {