drm/bridge: lontium-lt8912b: Do not generate HFP

[PATCH] drm/bridge: lontium-lt8912b: Do not generate HFP

Posted by max.oss.09@gmail.com 6 months, 1 week ago

From: Max Krummenacher <max.krummenacher@toradex.com>

The datasheet of lontium-lt8912b doesn't require blanking during
the HFP period. Thus use LP during HFP.

Tested with a samsung-dsim (i.MX8 MM) and a tc358768 DPI to DSI bridge
as the DSI host.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>

---

 drivers/gpu/drm/bridge/lontium-lt8912b.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/bridge/lontium-lt8912b.c b/drivers/gpu/drm/bridge/lontium-lt8912b.c
index 3e49d855b364..760d89493276 100644
--- a/drivers/gpu/drm/bridge/lontium-lt8912b.c
+++ b/drivers/gpu/drm/bridge/lontium-lt8912b.c
@@ -494,6 +494,7 @@ static int lt8912_attach_dsi(struct lt8912 *lt)
 
 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
 			  MIPI_DSI_MODE_LPM |
+			  MIPI_DSI_MODE_VIDEO_NO_HFP |
 			  MIPI_DSI_MODE_NO_EOT_PACKET;
 
 	ret = devm_mipi_dsi_attach(dev, dsi);
-- 
2.42.0

Re: [PATCH] drm/bridge: lontium-lt8912b: Do not generate HFP

Posted by Francesco Dolcini 4 months, 4 weeks ago

Hello all,

On Mon, Jul 28, 2025 at 05:00:50PM +0200, max.oss.09@gmail.com wrote:
> From: Max Krummenacher <max.krummenacher@toradex.com>
> 
> The datasheet of lontium-lt8912b doesn't require blanking during
> the HFP period. Thus use LP during HFP.
> 
> Tested with a samsung-dsim (i.MX8 MM) and a tc358768 DPI to DSI bridge
> as the DSI host.
> 
> Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>

Just a gently ping on this

Francesco

Re: [PATCH] drm/bridge: lontium-lt8912b: Do not generate HFP

Posted by Max Krummenacher 3 months, 1 week ago

On Thu, Sep 11, 2025 at 05:34:53PM +0200, Francesco Dolcini wrote:
> Hello all,
> 
> On Mon, Jul 28, 2025 at 05:00:50PM +0200, max.oss.09@gmail.com wrote:
> > From: Max Krummenacher <max.krummenacher@toradex.com>
> > 
> > The datasheet of lontium-lt8912b doesn't require blanking during
> > the HFP period. Thus use LP during HFP.
> > 
> > Tested with a samsung-dsim (i.MX8 MM) and a tc358768 DPI to DSI bridge
> > as the DSI host.
> > 
> > Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
> 
> Just a gently ping on this

Any opinion on this?
Max

> 
> Francesco