2023-09-22 21:47:49

by Xin Ji

Subject: [PATCH v2] drm/bridge: Add 200ms delay to wait FW HPD status stable

For the no-interrupt design (sink device is panel, polling HPD
status when chip power on), anx7625 FW has more than 200ms HPD
de-bounce time in FW, for the safety to get HPD status, driver
better to wait 200ms before HPD detection after OS resume back.

Signed-off-by: Xin Ji <[email protected]>
---
drivers/gpu/drm/bridge/analogix/anx7625.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 51abe42c639e..8f740154707d 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1464,6 +1464,9 @@ static int _anx7625_hpd_polling(struct anx7625_data *ctx,
if (ctx->pdata.intp_irq)
return 0;

+ /* Delay 200ms for FW HPD de-bounce */
+ msleep(200);
+
ret = readx_poll_timeout(anx7625_read_hpd_status_p0,
ctx, val,
((val & HPD_STATUS) || (val < 0)),
--
2.25.1

2023-09-25 11:55:23

by Robert Foss

Subject: Re: [PATCH v2] drm/bridge: Add 200ms delay to wait FW HPD status stable

On Fri, 22 Sep 2023 17:34:49 +0800, Xin Ji wrote:
> For the no-interrupt design (sink device is panel, polling HPD
> status when chip power on), anx7625 FW has more than 200ms HPD
> de-bounce time in FW, for the safety to get HPD status, driver
> better to wait 200ms before HPD detection after OS resume back.
>
>

Applied, thanks!

[1/1] drm/bridge: Add 200ms delay to wait FW HPD status stable
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=330140d7319f



Rob