Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755975Ab1BJKQ1 (ORCPT ); Thu, 10 Feb 2011 05:16:27 -0500 Received: from server109-228-6-236.live-servers.net ([109.228.6.236]:53919 "EHLO fireflyinternet.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755787Ab1BJKQZ (ORCPT ); Thu, 10 Feb 2011 05:16:25 -0500 X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.66.37; From: Chris Wilson To: Hugh Dickins Cc: Jesse Barnes , linux-kernel@vger.kernel.org, Chris Wilson , stable@kernel.org Subject: [PATCH] drm/i915/tv: Use polling rather than interrupt-based hotplug Date: Thu, 10 Feb 2011 10:16:06 +0000 Message-Id: <1297332966-17647-1-git-send-email-chris@chris-wilson.co.uk> X-Mailer: git-send-email 1.7.2.3 In-Reply-To: References: X-Originating-IP: 78.156.66.37 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4472 Lines: 113 The documentation recommends that we should use a polling method for TV detection as this is more power efficient than the interrupt based mechanism (as the encoder can be completely switched off). A secondary effect is that leaving the hotplug enabled seems to be causing pipe underruns as reported by Hugh Dickins on his Crestline. Signed-off-by: Chris Wilson Cc: stable@kernel.org --- Hugh, does this prevent the persistent PIPE UNDERRUN issue? --- drivers/gpu/drm/i915/intel_tv.c | 43 +++++++++++++++++++++++++++----------- 1 files changed, 30 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c index 93206e4..fe4a53a 100644 --- a/drivers/gpu/drm/i915/intel_tv.c +++ b/drivers/gpu/drm/i915/intel_tv.c @@ -1234,7 +1234,8 @@ static const struct drm_display_mode reported_modes[] = { * \return false if TV is disconnected. */ static int -intel_tv_detect_type (struct intel_tv *intel_tv) +intel_tv_detect_type (struct intel_tv *intel_tv, + struct drm_connector *connector) { struct drm_encoder *encoder = &intel_tv->base.base; struct drm_device *dev = encoder->dev; @@ -1245,11 +1246,13 @@ intel_tv_detect_type (struct intel_tv *intel_tv) int type; /* Disable TV interrupts around load detect or we'll recurse */ - spin_lock_irqsave(&dev_priv->irq_lock, irqflags); - i915_disable_pipestat(dev_priv, 0, - PIPE_HOTPLUG_INTERRUPT_ENABLE | - PIPE_HOTPLUG_TV_INTERRUPT_ENABLE); - spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags); + if (connector->polled & DRM_CONNECTOR_POLL_HPD) { + spin_lock_irqsave(&dev_priv->irq_lock, irqflags); + i915_disable_pipestat(dev_priv, 0, + PIPE_HOTPLUG_INTERRUPT_ENABLE | + PIPE_HOTPLUG_TV_INTERRUPT_ENABLE); + spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags); + } save_tv_dac = tv_dac = I915_READ(TV_DAC); save_tv_ctl = tv_ctl = I915_READ(TV_CTL); @@ -1302,11 +1305,13 @@ intel_tv_detect_type (struct intel_tv *intel_tv) I915_WRITE(TV_CTL, save_tv_ctl); /* Restore interrupt config */ - spin_lock_irqsave(&dev_priv->irq_lock, irqflags); - i915_enable_pipestat(dev_priv, 0, - PIPE_HOTPLUG_INTERRUPT_ENABLE | - PIPE_HOTPLUG_TV_INTERRUPT_ENABLE); - spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags); + if (connector->polled & DRM_CONNECTOR_POLL_HPD) { + spin_lock_irqsave(&dev_priv->irq_lock, irqflags); + i915_enable_pipestat(dev_priv, 0, + PIPE_HOTPLUG_INTERRUPT_ENABLE | + PIPE_HOTPLUG_TV_INTERRUPT_ENABLE); + spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags); + } return type; } @@ -1356,7 +1361,7 @@ intel_tv_detect(struct drm_connector *connector, bool force) drm_mode_set_crtcinfo(&mode, CRTC_INTERLACE_HALVE_V); if (intel_tv->base.base.crtc && intel_tv->base.base.crtc->enabled) { - type = intel_tv_detect_type(intel_tv); + type = intel_tv_detect_type(intel_tv, connector); } else if (force) { struct drm_crtc *crtc; int dpms_mode; @@ -1364,7 +1369,7 @@ intel_tv_detect(struct drm_connector *connector, bool force) crtc = intel_get_load_detect_pipe(&intel_tv->base, connector, &mode, &dpms_mode); if (crtc) { - type = intel_tv_detect_type(intel_tv); + type = intel_tv_detect_type(intel_tv, connector); intel_release_load_detect_pipe(&intel_tv->base, connector, dpms_mode); } else @@ -1658,6 +1663,18 @@ intel_tv_init(struct drm_device *dev) intel_encoder = &intel_tv->base; connector = &intel_connector->base; + /* The documentation, for the older chipsets at least, recommend + * using a polling method rather than hotplug detection for TVs. + * This is because in order to perform the hotplug detection, the PLLs + * for the TV must be kept alive increasing power drain and starving + * bandwidth from other encoders. Notably for instance, it causes + * pipe underruns on Crestline when this encoder is supposedly idle. + * + * More recent chipsets favour HDMI rather than integrated S-Video. + */ + connector->polled = + DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT; + drm_connector_init(dev, connector, &intel_tv_connector_funcs, DRM_MODE_CONNECTOR_SVIDEO); -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/