Re: [PATCH] sn65dsi83.c: fix dual-channel LVDS output also divide porches

On Tue, Nov 26, 2024 at 09:42:45AM +0000, Bauer, Markus wrote:

sn65dsi83.c: fix dual-channel LVDS output also divide porches

Please use drm/bridge: ti-sn65dsi83: as subject prefix. Drop the first line of the commit message.

When generating dual-channel LVDS to a single display, the horizontal part has to be divided in halves for each channel. This was done correctly for hactive, but not for the porches.

I don't see this being handled for hactive. Could you please point out the code?

Of course this does only apply to sn65dsi84, which is also covered by this driver.

Cc: stable@vger.kernel.org

Also:

Fixes: ceb515ba29ba ("drm/bridge: ti-sn65dsi83: Add TI SN65DSI83 and SN65DSI84 driver")

Signed-off-by: Markus Bauer markus.bauer2@avnet.com

drivers/gpu/drm/bridge/ti-sn65dsi83.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c index ad73f69d768d..d71f752e79ec 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c @@ -399,7 +399,7 @@ static void sn65dsi83_atomic_pre_enable(struct drm_bridge *bridge, unsigned int pval; __le16 le16val; u16 val;

• int ret;

• int ret, hfront, hback;

ret = regulator_enable(ctx->vcc); if (ret) { @@ -521,12 +521,22 @@ static void sn65dsi83_atomic_pre_enable(struct drm_bridge *bridge, le16val = cpu_to_le16(mode->vsync_end - mode->vsync_start); regmap_bulk_write(ctx->regmap, REG_VID_CHA_VSYNC_PULSE_WIDTH_LOW, &le16val, 2);

• hback = mode->htotal - mode->hsync_end;
• if (ctx->lvds_dual_link)

• hback /= 2;
  

• regmap_write(ctx->regmap, REG_VID_CHA_HORIZONTAL_BACK_PORCH,

•      mode->htotal - mode->hsync_end);
  

•      hback);
  

  regmap_write(ctx->regmap, REG_VID_CHA_VERTICAL_BACK_PORCH, mode->vtotal - mode->vsync_end);
• hfront = mode->hsync_start - mode->hdisplay;
• if (ctx->lvds_dual_link)

• hfront /= 2;
  

• regmap_write(ctx->regmap, REG_VID_CHA_HORIZONTAL_FRONT_PORCH,

•      mode->hsync_start - mode->hdisplay);
  

•      hfront);
  

  regmap_write(ctx->regmap, REG_VID_CHA_VERTICAL_FRONT_PORCH, mode->vsync_start - mode->vdisplay); regmap_write(ctx->regmap, REG_VID_CHA_TEST_PATTERN, 0x00);

-- 2.34.1

-- Markus Bauer

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