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drm/i915: Configure the TV sense state correctly on GM45 to make TV d…
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…etection reliable

The TV detection logic is not reliable on the Cantiga platform.
Sometimes the TV will be misdetected as the following two cases:
- TV is misdetected on some laptops. e.g. There is no TV connector
port or no TV is attached. But the TV is shown as connected.
- TV connector type is misdetected. e.g. the component TV is
attached, but the TV is shown as S-video type.

According to the hardware requirement, the TV sense state bits of TV DAC
register should be cleared to zero on Cantiga platfrom.

https://bugzilla.kernel.org/show_bug.cgi?id=14792

Cc: Stable Team <stable@kernel.org>
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Tested-by: Santi <santi@agolina.net>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
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Zhao Yakui authored and Eric Anholt committed Apr 10, 2010
1 parent bfac4d6 commit fb8b5a3
Showing 1 changed file with 9 additions and 0 deletions.
9 changes: 9 additions & 0 deletions drivers/gpu/drm/i915/intel_tv.c
Original file line number Diff line number Diff line change
Expand Up @@ -1399,6 +1399,15 @@ intel_tv_detect_type (struct drm_crtc *crtc, struct intel_encoder *intel_encoder
DAC_A_0_7_V |
DAC_B_0_7_V |
DAC_C_0_7_V);

/*
* The TV sense state should be cleared to zero on cantiga platform. Otherwise
* the TV is misdetected. This is hardware requirement.
*/
if (IS_GM45(dev))
tv_dac &= ~(TVDAC_STATE_CHG_EN | TVDAC_A_SENSE_CTL |
TVDAC_B_SENSE_CTL | TVDAC_C_SENSE_CTL);

I915_WRITE(TV_CTL, tv_ctl);
I915_WRITE(TV_DAC, tv_dac);
intel_wait_for_vblank(dev);
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