diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_display.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 335822e6ddb9..fbcfed63a76e 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -9512,6 +9512,24 @@ static void ironlake_compute_dpll(struct intel_crtc *intel_crtc, if (intel_crtc_has_dp_encoder(crtc_state)) dpll |= DPLL_SDVO_HIGH_SPEED; + /* + * The high speed IO clock is only really required for + * SDVO/HDMI/DP, but we also enable it for CRT to make it + * possible to share the DPLL between CRT and HDMI. Enabling + * the clock needlessly does no real harm, except use up a + * bit of power potentially. + * + * We'll limit this to IVB with 3 pipes, since it has only two + * DPLLs and so DPLL sharing is the only way to get three pipes + * driving PCH ports at the same time. On SNB we could do this, + * and potentially avoid enabling the second DPLL, but it's not + * clear if it''s a win or loss power wise. No point in doing + * this on ILK at all since it has a fixed DPLL<->pipe mapping. + */ + if (INTEL_INFO(dev_priv)->num_pipes == 3 && + intel_crtc_has_type(crtc_state, INTEL_OUTPUT_ANALOG)) + dpll |= DPLL_SDVO_HIGH_SPEED; + /* compute bitmask from p1 value */ dpll |= (1 << (crtc_state->dpll.p1 - 1)) << DPLL_FPA01_P1_POST_DIV_SHIFT; /* also FPA1 */ |