From 76a5a5a328ad95a40a266d5167644d15f385eac4 Mon Sep 17 00:00:00 2001 From: Yakir Yang Date: Tue, 8 Sep 2015 21:13:53 -0500 Subject: [PATCH] CHROMIUM: drm: bridge/dw_hdmi: switch ddc mode to standard mode DDC have two modes: fast mode, standard mode. The previous ddc support patch(https://chromium-review.googlesource.com/#/c/292012/) configure the ddc to fast mode. It works rightly in most HDTV case, but I found that ddc would always failed if I used the VGA->HDMI adapter. And after I switch ddc to standard mode, no failed anymore. I believe the standard mode could provide better compatibility. BUG=chrome-os-partner:34741 TEST=My VGA->HDMI adapter can read edid now Change-Id: Ia33ade0a4fda998483baf454b9ccb9f31802f6bc Signed-off-by: Yakir Yang Reviewed-on: https://chromium-review.googlesource.com/298270 Commit-Ready: Douglas Anderson Tested-by: Douglas Anderson Reviewed-by: Douglas Anderson Reviewed-by: Tomasz Figa --- drivers/gpu/drm/bridge/dw-hdmi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c index 8bf46d863bd3..361c8c804da3 100644 --- a/drivers/gpu/drm/bridge/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/dw-hdmi.c @@ -271,8 +271,8 @@ static void hdmi_mask_writeb(struct dw_hdmi *hdmi, u8 data, unsigned int reg, static void dw_hdmi_i2c_init(struct dw_hdmi *hdmi) { - /* Set Fast Mode speed */ - hdmi_writeb(hdmi, 0x0b, HDMI_I2CM_DIV); + /* Set Standard Mode speed */ + hdmi_writeb(hdmi, 0x03, HDMI_I2CM_DIV); /* Software reset */ hdmi_writeb(hdmi, 0x00, HDMI_I2CM_SOFTRSTZ); -- 2.34.1