From c231775c2df845abc193666a5aec552c3ad3740f Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Tue, 15 Mar 2016 16:39:56 +0200 Subject: [PATCH] drm/i915: Implement WaPixelRepeatModeFixForC0:chv MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit DPLL_MD(PIPE_C) is AWOL on CHV. Instead of fixing it someone added chicken bits to propagate the pixel multiplier from DPLL_MD(PIPE_B) to either pipe B or C. So do that to make pixel repeat work on pipes B and C. Pipe A is fine without any tricks. Fortunately the pixel repeat propagation appears to be a oneshot operation, so once the value has been written we can clear the chicken bits. So it is still possible to drive pipe B and C with different pixel multipliers simultaneosly. Looks like DPLL_VGA_MODE_DIS must also be set in DPLL(PIPE_B) for this to work. But since we keep that bit always set in all DPLLs there's no problem. This of course means we can't reliably read out the pixel multiplier for pipes B and C. That would make the state checker unhappy, so I added shadow copies of those registers in to dev_priv. The other option would have been to skip pixel multiplier, dpll_md an dotclock checks entirely on CHV, but that feels like a serious loss of cross checking, so just pretending that we have working DPLL MD registers seemed better. Obviously with the shadow copies we can't detect if the pixel multiplier was properly configured, nor can we take over its state from the BIOS, but hopefully people won't have displays that would be limitd to such crappy modes. There is one strange flicker still remaining. It's visible on pipe C/HDMID when HDMIB is enabled while driven by pipe B. It doesn't occur if pipe A drives HDMIB, nor is there any glitch on pipe B/HDMIB when port C/HDMID starts up. I don't have a board with HDMIC so not sure if it happens there too. So I'm not sure if it's somehow tied in with this strange linkage between pipe B and C. Sadly I was unable to find an enable sequence that would avoid the glitch, but at least it's not fatal ie. the output recovers afterwards. Signed-off-by: Ville Syrjälä Link: http://patchwork.freedesktop.org/patch/msgid/1458052809-23426-4-git-send-email-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula --- drivers/gpu/drm/i915/i915_drv.h | 7 +++++++ drivers/gpu/drm/i915/i915_reg.h | 4 ++++ drivers/gpu/drm/i915/intel_display.c | 30 ++++++++++++++++++++++++---- 3 files changed, 37 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index d3ebb2fa46fa..dd187727c813 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1900,7 +1900,14 @@ struct drm_i915_private { u32 fdi_rx_config; + /* Shadow for DISPLAY_PHY_CONTROL which can't be safely read */ u32 chv_phy_control; + /* + * Shadows for CHV DPLL_MD regs to keep the state + * checker somewhat working in the presence hardware + * crappiness (can't read out DPLL_MD for pipes B & C). + */ + u32 chv_dpll_md[I915_MAX_PIPES]; u32 suspend_count; bool suspended_to_idle; diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 6df3c59fb192..12f510381273 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -4786,6 +4786,10 @@ enum skl_disp_power_wells { #define CBR_PND_DEADLINE_DISABLE (1<<31) #define CBR_PWM_CLOCK_MUX_SELECT (1<<30) +#define CBR4_VLV _MMIO(VLV_DISPLAY_BASE + 0x70450) +#define CBR_DPLLBMD_PIPE_C (1<<29) +#define CBR_DPLLBMD_PIPE_B (1<<18) + /* FIFO watermark sizes etc */ #define G4X_FIFO_LINE_SIZE 64 #define I915_FIFO_LINE_SIZE 64 diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 05287480078d..3fdce859758a 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -1591,9 +1591,27 @@ static void chv_enable_pll(struct intel_crtc *crtc, if (wait_for(((I915_READ(DPLL(pipe)) & DPLL_LOCK_VLV) == DPLL_LOCK_VLV), 1)) DRM_ERROR("PLL %d failed to lock\n", pipe); - /* not sure when this should be written */ - I915_WRITE(DPLL_MD(pipe), pipe_config->dpll_hw_state.dpll_md); - POSTING_READ(DPLL_MD(pipe)); + if (pipe != PIPE_A) { + /* + * WaPixelRepeatModeFixForC0:chv + * + * DPLLCMD is AWOL. Use chicken bits to propagate + * the value from DPLLBMD to either pipe B or C. + */ + I915_WRITE(CBR4_VLV, pipe == PIPE_B ? CBR_DPLLBMD_PIPE_B : CBR_DPLLBMD_PIPE_C); + I915_WRITE(DPLL_MD(PIPE_B), pipe_config->dpll_hw_state.dpll_md); + I915_WRITE(CBR4_VLV, 0); + dev_priv->chv_dpll_md[pipe] = pipe_config->dpll_hw_state.dpll_md; + + /* + * DPLLB VGA mode also seems to cause problems. + * We should always have it disabled. + */ + WARN_ON((I915_READ(DPLL(PIPE_B)) & DPLL_VGA_MODE_DIS) == 0); + } else { + I915_WRITE(DPLL_MD(pipe), pipe_config->dpll_hw_state.dpll_md); + POSTING_READ(DPLL_MD(pipe)); + } } static int intel_num_dvo_pipes(struct drm_device *dev) @@ -8156,7 +8174,11 @@ static bool i9xx_get_pipe_config(struct intel_crtc *crtc, i9xx_get_pfit_config(crtc, pipe_config); if (INTEL_INFO(dev)->gen >= 4) { - tmp = I915_READ(DPLL_MD(crtc->pipe)); + /* No way to read it out on pipes B and C */ + if (IS_CHERRYVIEW(dev) && crtc->pipe != PIPE_A) + tmp = dev_priv->chv_dpll_md[crtc->pipe]; + else + tmp = I915_READ(DPLL_MD(crtc->pipe)); pipe_config->pixel_multiplier = ((tmp & DPLL_MD_UDI_MULTIPLIER_MASK) >> DPLL_MD_UDI_MULTIPLIER_SHIFT) + 1; -- 2.20.1