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drm/i915: rip out pre-production ilk cpu edp w/a

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While reading docs I've noticed that this special workaround to select
the 1.6 GHz DP clock only applies to pre-production ilk machines.
Since the registers we're touching here are rather undocumented and
might be harmful on later chips, rip it out.

For the Bspec reference of this w/a look in "vol4g CPU Display
Registers [DevILK]", Section 4.1.7.1 "DP_A—DisplayPort A
Control Register", "DP_PLL_Frequency_Select".

v2: Keep a debug message as a hint in case something regresses.
Requested by Chris Wilson.

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Daniel Vetter 2012-11-29 15:59:32 +01:00
parent ea9b6006b5
commit 1ce1703809
1 changed files with 5 additions and 16 deletions
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21
drivers/gpu/drm/i915/intel_dp.c
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@ -910,26 +910,15 @@ static void ironlake_set_pll_edp(struct drm_crtc *crtc, int clock)
dpa_ctl &= ~DP_PLL_FREQ_MASK;
if (clock < 200000) {
u32 temp;
/* For a long time we've carried around a ILK-DevA w/a for the
* 160MHz clock. If we're really unlucky, it's still required.
*/
DRM_DEBUG_KMS("160MHz cpu eDP clock, might need ilk devA w/a\n");
dpa_ctl |= DP_PLL_FREQ_160MHZ;
/* workaround for 160Mhz:
1) program 0x4600c bits 15:0 = 0x8124
2) program 0x46010 bit 0 = 1
3) program 0x46034 bit 24 = 1
4) program 0x64000 bit 14 = 1
*/
temp = I915_READ(0x4600c);
temp &= 0xffff0000;
I915_WRITE(0x4600c, temp | 0x8124);
temp = I915_READ(0x46010);
I915_WRITE(0x46010, temp | 1);
temp = I915_READ(0x46034);
I915_WRITE(0x46034, temp | (1 << 24));
} else {
dpa_ctl |= DP_PLL_FREQ_270MHZ;
}
I915_WRITE(DP_A, dpa_ctl);
POSTING_READ(DP_A);