The pins for ddc and aux are shared so you need to switch the mode when doing ddc. The ProcessAuxChannel table already sets the pin mode to DP. This should fix unreliable ddc issues on DP ports using non-DP monitors.

Signed-off-by: Alex Deucher alexdeucher@gmail.com Cc: stable@kernel.org --- drivers/gpu/drm/radeon/radeon_i2c.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c index ea15e62..6a13ee3 100644 --- a/drivers/gpu/drm/radeon/radeon_i2c.c +++ b/drivers/gpu/drm/radeon/radeon_i2c.c @@ -99,6 +99,13 @@ static void radeon_i2c_do_lock(struct radeon_i2c_chan *i2c, int lock_state) } }

+ /* switch the pads to ddc mode */ + if (ASIC_IS_DCE3(rdev) && rec->hw_capable) { + temp = RREG32(rec->mask_clk_reg); + temp &= ~(1 << 16); + WREG32(rec->mask_clk_reg, temp); + } + /* clear the output pin values */ temp = RREG32(rec->a_clk_reg) & ~rec->a_clk_mask; WREG32(rec->a_clk_reg, temp);