From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751314Ab2AUUxI (ORCPT ); Sat, 21 Jan 2012 15:53:08 -0500 Received: from home.keithp.com ([63.227.221.253]:44643 "EHLO keithp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750899Ab2AUUxG (ORCPT ); Sat, 21 Jan 2012 15:53:06 -0500 From: Keith Packard To: Lubos Kolouch Cc: linux-kernel@vger.kernel.org Subject: Re: i915 wakes from suspend to RAM with blank screen after commit cd9dde44f47501394b9f0715b6a36a92aa74c0d0 In-Reply-To: <20120121184453.GA2698@nbgentoo> References: <86mx9gkjlv.fsf@sumi.keithp.com> <20120121184453.GA2698@nbgentoo> User-Agent: Notmuch/0.11 (http://notmuchmail.org) Emacs/23.3.1 (i486-pc-linux-gnu) Date: Sat, 21 Jan 2012 12:53:00 -0800 Message-ID: <86hazokcb7.fsf@sumi.keithp.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Type: multipart/signed; boundary="==-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" --==-=-= On Sat, 21 Jan 2012 19:44:53 +0100, Lubos Kolouch wrote: > dmesg after boot - http://paste.pocoo.org/show/538343/ > dmesg after failed resume - http://paste.pocoo.org/show/538344/ Ok, that's weird -- we're choosing a different display port link speed on resume than at boot time. I have a theory that intel_dp_mode_fixup is accidentally using the current bpp value when computing the values needed for the new mode, and that this value may differ between boot and resume. Here's a patch to dump some debug info out to test this theory. --==-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIVAwUBTxslrDYtFsjWk68qAQghJg/8CS7tuKhL0umzslKhGvJyL4+MuXuVXFfb WRe0tAR1n8ulBQ/9uEvzu2f13d3MvB9JvNKf+e/xgiSEwnkYD+qF5xVaXIzSU4cq 1n7ChIfkK45qISn8+wxVcOzUFyX0BYhu0sti+CsJABU6YV7x8HRXsPM7J1M9sEaK TUAnHKPP/wiCX2fM4osZABRqTijLRdiFfuNI6fqPadhtIuCm68cSivji4rcLgTco V8ztQ6ukd34lSjx8zmXQolD64vWtzqaq9iXev6I+zGK4MVNu7iYcdtbDbjtgz3o5 qw/j5L9ozP5c9k/djiKBbhb3MuPQtBOlliAsW2QtmKEsFdabkjLo5uLC1CHOt/ES Xbak9W7ejwcHqmZRQmMaMUuKECItdRWtHUpMBAvcXRRb+tejyShhYXDkxwb4icx0 0gZ8CBOP4rJ5X4Cl1o1CcCtQlVRoCTwib+t6Ea5iUK8cdaeqcb751ywZqL4x8h3O qUtMmH1Lrk4wgrHyW9IIvp3WOXWZ7oAAdu7n/rOODf7q9YmpFAKgEJJZOJUwhBO/ 2HAm0eUct8Jpj7w6F1vQwXOGpIqPzbJoQjoYVpWLWDSdM9nlp4u7G7fVPwp/aXWJ pHJ+V2vOyyfFQlg3aem4iDqo6WxbWSdpTEY7U9rNVE8/l0DS5E9COQEp85uvKkBV 8A587rtsBpo= =AqYt -----END PGP SIGNATURE----- --==-=-=-- --=-=-= Content-Type: text/x-diff Content-Disposition: inline; filename=0001-drm-i915-Output-a-bit-of-debug-info-for-display-port.patch >>From 2b16db9fccc6927f3e09020144d5148acc025f58 Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Sat, 21 Jan 2012 12:48:38 -0800 Subject: [PATCH] drm/i915: Output a bit of debug info for display port bandwidth Something weird is going on with link bandwidth testing; this may help sort out what's wrong. Signed-off-by: Keith Packard --- drivers/gpu/drm/i915/intel_dp.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index db3b461..796d534 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -697,10 +697,13 @@ intel_dp_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode, mode->clock = intel_dp->panel_fixed_mode->clock; } + DRM_DEBUG_KMS("using bpp %d to find link_bw and lane_count\n", bpp); for (lane_count = 1; lane_count <= max_lane_count; lane_count <<= 1) { for (clock = 0; clock <= max_clock; clock++) { int link_avail = intel_dp_max_data_rate(intel_dp_link_clock(bws[clock]), lane_count); + DRM_DEBUG_KMS("lane_count %d clock %d link_avail %d link_required %d\n", + lane_count, clock, link_avail, intel_dp_link_required(intel_dp, mode->clock, bpp)); if (intel_dp_link_required(intel_dp, mode->clock, bpp) <= link_avail) { intel_dp->link_bw = bws[clock]; -- 1.7.8.3 --=-=-= Please try this on the broken kernel, sending along the dmesg output at boot and resume time again. -- keith.packard@intel.com --=-=-=--