From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paulo Zanoni Subject: [PATCH 3/3] drm/i915: set the LPT FDI RX polarity reversal bit when needed Date: Sat, 1 Dec 2012 12:04:26 -0200 Message-ID: <1354370666-3802-4-git-send-email-przanoni@gmail.com> References: <1354370666-3802-1-git-send-email-przanoni@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ye0-f177.google.com (mail-ye0-f177.google.com [209.85.213.177]) by gabe.freedesktop.org (Postfix) with ESMTP id 3705AE68AC for ; Sat, 1 Dec 2012 06:05:00 -0800 (PST) Received: by mail-ye0-f177.google.com with SMTP id q13so213573yen.36 for ; Sat, 01 Dec 2012 06:04:59 -0800 (PST) In-Reply-To: <1354370666-3802-1-git-send-email-przanoni@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: intel-gfx@lists.freedesktop.org Cc: Paulo Zanoni List-Id: intel-gfx@lists.freedesktop.org From: Paulo Zanoni If we fail to set the bit when needed we get some nice FDI link training failures (AKA "black screen on VGA output"). While we don't really know how to properly choose whether we need to set the bit or not (VBT?), just read the initial value set by the BIOS and store it for later usage. Signed-off-by: Paulo Zanoni --- drivers/gpu/drm/i915/i915_drv.h | 2 ++ drivers/gpu/drm/i915/i915_reg.h | 1 + drivers/gpu/drm/i915/intel_crt.c | 8 ++++++++ drivers/gpu/drm/i915/intel_ddi.c | 2 ++ 4 files changed, 13 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 65213bc..557843d 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -915,6 +915,8 @@ typedef struct drm_i915_private { bool hw_contexts_disabled; uint32_t hw_context_size; + bool fdi_rx_polarity_reversed; + struct i915_suspend_saved_registers regfile; /* Old dri1 support infrastructure, beware the dragons ya fools entering diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index acf768d..3f75cfa 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -3917,6 +3917,7 @@ #define FDI_FS_ERRC_ENABLE (1<<27) #define FDI_FE_ERRC_ENABLE (1<<26) #define FDI_DP_PORT_WIDTH_X8 (7<<19) +#define FDI_RX_POLARITY_REVERSED_LPT (1<<16) #define FDI_8BPC (0<<16) #define FDI_10BPC (1<<16) #define FDI_6BPC (2<<16) diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c index 3084d01..fe20bf7 100644 --- a/drivers/gpu/drm/i915/intel_crt.c +++ b/drivers/gpu/drm/i915/intel_crt.c @@ -798,4 +798,12 @@ void intel_crt_init(struct drm_device *dev) crt->force_hotplug_required = 0; dev_priv->hotplug_supported_mask |= CRT_HOTPLUG_INT_STATUS; + + /* + * TODO: find a proper way to discover whether we need to set the + * polarity reversal bit or not, instead of relying on the BIOS. + */ + if (HAS_PCH_LPT(dev)) + dev_priv->fdi_rx_polarity_reversed = + !!(I915_READ(_FDI_RXA_CTL) & FDI_RX_POLARITY_REVERSED_LPT); } diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index 3264cb4..4bad0f7 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -180,6 +180,8 @@ void hsw_fdi_link_train(struct drm_crtc *crtc) /* Enable the PCH Receiver FDI PLL */ rx_ctl_val = FDI_RX_PLL_ENABLE | FDI_RX_ENHANCE_FRAME_ENABLE | ((intel_crtc->fdi_lanes - 1) << 19); + if (dev_priv->fdi_rx_polarity_reversed) + rx_ctl_val |= FDI_RX_POLARITY_REVERSED_LPT; I915_WRITE(_FDI_RXA_CTL, rx_ctl_val); POSTING_READ(_FDI_RXA_CTL); udelay(220); -- 1.7.11.7