From debded848dee028d7f1f1e42a4e118df9636fb84 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Wed, 17 Feb 2016 21:41:13 +0200 Subject: [PATCH] drm/i915: Try to fix CRT port clock limits MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit LPT/WPT-H are limited to max 180 MHz CRT dotclock. Most other platforms have a limit of 350 MHz. Supposedly gen3 and gen4 go up to 400 MHz. VLV is a bit special since the docs are poor. Supposedly the DAC would be good up to 355 MHz, but currently we limit the DPLL to 270 MHz, so we'll have to limit the port clock to the same unless we change the DPLL limits. Signed-off-by: Ville Syrjälä Link: http://patchwork.freedesktop.org/patch/msgid/1455738073-14502-7-git-send-email-ville.syrjala@linux.intel.com Reviewed-by: Imre Deak --- drivers/gpu/drm/i915/intel_crt.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c index 61eaac2f326d..583cae744a1a 100644 --- a/drivers/gpu/drm/i915/intel_crt.c +++ b/drivers/gpu/drm/i915/intel_crt.c @@ -218,18 +218,26 @@ intel_crt_mode_valid(struct drm_connector *connector, { struct drm_device *dev = connector->dev; int max_dotclk = to_i915(dev)->max_dotclk_freq; + int max_clock; - int max_clock = 0; if (mode->flags & DRM_MODE_FLAG_DBLSCAN) return MODE_NO_DBLESCAN; if (mode->clock < 25000) return MODE_CLOCK_LOW; - if (IS_GEN2(dev)) - max_clock = 350000; - else + if (HAS_PCH_LPT(dev)) + max_clock = 180000; + else if (IS_VALLEYVIEW(dev)) + /* + * 270 MHz due to current DPLL limits, + * DAC limit supposedly 355 MHz. + */ + max_clock = 270000; + else if (IS_GEN3(dev) || IS_GEN4(dev)) max_clock = 400000; + else + max_clock = 350000; if (mode->clock > max_clock) return MODE_CLOCK_HIGH; -- 2.20.1