[Intel-gfx] [PATCH] drm/i915: Update HDMI max TMDS data rate definition for VBT

[Chiou, Cooper]

Hi Ville,

The bits is 5-7 means it’s 001x xxxx for 2.97Gbps, and 010x xxxx for 1.65Gbps.
So correct value should be 2 not 1 for HDMI_MAX_DATA_RATE_297.
And HDMI_MAX_DATA_RATE_165 is 4 not 2.

I checked kernel i915 log and modified VBT to limit HDMI 1.4 from HDMI 2.0 then found this error. And I run CrOS on GLK with changed VBT to validate it. Thanks,

Best Regards,
Cooper

On Apr 9, 2019, at 8:45 PM, Ville Syrjälä <ville.syrjala at linux.intel.com<mailto:ville.syrjala at linux.intel.com>> wrote:

On Tue, Apr 09, 2019 at 06:07:08PM +0800, Chiou, Cooper wrote:
VBT version 212 defined HDMI max. bit-rate 2.97Gbps is 0x02 and 1.65Gbps
is 0x04, so changed HDMI_MAX_DATA_RATE_297/HDMI_MAX_DATA_RATE_165 to map
correct values

Eh what? Did someone just change the interpretation of these bits?

Per VBT BSpec definition in HDMI max. data rate, Bits7-5 is HDMI max. data
rate 000=Default, 001=2.97Gbps, 010=1.65Gbps,

Here you're quoting the values we already use...

so HDMI_MAX_DATA_RATE_297
should be 2 and HDMI_MAX_DATA_RATE_165 should be 4

...but here you're using different values again? Which way is it?


TEST: Validated PASS on GLK RVP platform

Cc: Jani Nikula <jani.nikula at intel.com<mailto:jani.nikula at intel.com>>
Signed-off-by: Chiou, Cooper <cooper.chiou at intel.com<mailto:cooper.chiou at intel.com>>
---
drivers/gpu/drm/i915/intel_vbt_defs.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_vbt_defs.h b/drivers/gpu/drm/i915/intel_vbt_defs.h
index bf3662ad5fed..e2b8d042912b 100644
--- a/drivers/gpu/drm/i915/intel_vbt_defs.h
+++ b/drivers/gpu/drm/i915/intel_vbt_defs.h
@@ -307,8 +307,8 @@ struct bdb_general_features {
#define DVO_PORT_MIPID        24                /* 171 */

#define HDMI_MAX_DATA_RATE_PLATFORM    0            /* 204 */
-#define HDMI_MAX_DATA_RATE_297        1            /* 204 */
-#define HDMI_MAX_DATA_RATE_165        2            /* 204 */
+#define HDMI_MAX_DATA_RATE_297        2            /* 212 */
+#define HDMI_MAX_DATA_RATE_165        4            /* 212 */

#define LEGACY_CHILD_DEVICE_CONFIG_SIZE        33

--
2.7.4

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--
Ville Syrjälä
Intel
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