[PATCH v2 0/1] Regression in analogix_anx78xx

[PATCH v2 0/1] Regression in analogix_anx78xx

[Tobias Schramm]

commit ff1e8fb68ea0 ("drm/bridge: analogix-anx78xx: Avoid drm_dp_link helpers")
stores the max link rate in a u8, overflowing it.
This will probably prevent the link training from working.

I've not tested this patch beyond a simple compile test since I do not own
any devices containing an anx78xx. So please test!


Best regards,

Tobias

Changelog:
 v2: Skip forward and back conversion to/from link rate

Tobias Schramm (1):
  drm/bridge: anx78xx: fix calculation of dp link rate

 drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

-- 
2.24.1

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[PATCH v2 1/1] drm/bridge: anx78xx: fix calculation of dp link rate

[Tobias Schramm]

commit ff1e8fb68ea0 ("drm/bridge: analogix-anx78xx: Avoid drm_dp_link helpers")
changed the link training logic to remove use of drm_dp_link helpers.
However the new logic stores the maximum link rate in a u8, overflowing
it.
This commit changes the logic to store the bw code directly, avoiding any
overflows.

Fixes: ff1e8fb68ea0 ("drm/bridge: analogix-anx78xx: Avoid drm_dp_link helpers")
Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
---
 drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
index 41867be03751..0c6b049b5753 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
@@ -722,8 +722,7 @@ static int anx78xx_dp_link_training(struct anx78xx *anx78xx)
 	if (err)
 		return err;
 
-	dpcd[0] = drm_dp_max_link_rate(anx78xx->dpcd);
-	dpcd[0] = drm_dp_link_rate_to_bw_code(dpcd[0]);
+	dpcd[0] = anx78xx->dpcd[DP_MAX_LINK_RATE];
 	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
 			   SP_DP_MAIN_LINK_BW_SET_REG, dpcd[0]);
 	if (err)
-- 
2.24.1

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