From patchwork Tue Nov 1 18:47:59 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dhinakaran Pandiyan X-Patchwork-Id: 9407841 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id ACCAF60234 for ; Tue, 1 Nov 2016 18:51:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9F83729A64 for ; Tue, 1 Nov 2016 18:51:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9260229A74; Tue, 1 Nov 2016 18:51:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9B45429A64 for ; Tue, 1 Nov 2016 18:51:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8B34189A0F; Tue, 1 Nov 2016 18:51:07 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 27B0489A0F for ; Tue, 1 Nov 2016 18:51:06 +0000 (UTC) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga104.fm.intel.com with ESMTP; 01 Nov 2016 11:51:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,580,1473145200"; d="scan'208";a="186431487" Received: from nuc-skylake.jf.intel.com ([10.54.75.23]) by fmsmga004.fm.intel.com with ESMTP; 01 Nov 2016 11:51:06 -0700 From: Dhinakaran Pandiyan To: intel-gfx@lists.freedesktop.org Date: Tue, 1 Nov 2016 11:47:59 -0700 Message-Id: <1478026080-2925-1-git-send-email-dhinakaran.pandiyan@intel.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Cc: Jani Nikula , stable@vger.kernel.org, Dhinakaran Pandiyan Subject: [Intel-gfx] [PATCH v4 1/2] drm/i915/dp: BDW cdclk fix for DP audio X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP According to BSpec, cdclk for BDW has to be not less than 432 MHz with DP audio enabled, port width x4, and link rate HBR2 (5.4 GHz). With cdclk less than 432 MHz, enabling audio leads to pipe FIFO underruns and displays cycling on/off. From BSpec: "Display» BDW-SKL» dpr» [Register] DP_TP_CTL [BDW+,EXCLUDE(CHV)] Workaround : Do not use DisplayPort with CDCLK less than 432 MHz, audio enabled, port width x4, and link rate HBR2 (5.4 GHz), or else there may be audio corruption or screen corruption." Since, some DP configurations (e.g., MST) use port width x4 and HBR2 link rate, let's increase the cdclk to >= 432 MHz to enable audio for those cases. v4: Changed commit message v3: Combine BDW pixel rate adjustments into a function (Jani) v2: Restrict fix to BDW Retain the set cdclk across modesets (Ville) Cc: stable@vger.kernel.org Signed-off-by: Dhinakaran Pandiyan Reviewed-by: Ville Syrjälä Reviewed-by: Jani Nikula --- drivers/gpu/drm/i915/intel_display.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 895b3dc..37483ee 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -10261,6 +10261,27 @@ static void bxt_modeset_commit_cdclk(struct drm_atomic_state *old_state) bxt_set_cdclk(to_i915(dev), req_cdclk); } +static int bdw_adjust_min_pipe_pixel_rate(struct intel_crtc_state *crtc_state, + int pixel_rate) +{ + /* pixel rate mustn't exceed 95% of cdclk with IPS on BDW */ + if (crtc_state->ips_enabled) + pixel_rate = DIV_ROUND_UP(pixel_rate * 100, 95); + + /* BSpec says "Do not use DisplayPort with CDCLK less than + * 432 MHz, audio enabled, port width x4, and link rate + * HBR2 (5.4 GHz), or else there may be audio corruption or + * screen corruption." + */ + if (intel_crtc_has_dp_encoder(crtc_state) && + crtc_state->has_audio && + crtc_state->port_clock >= 540000 && + crtc_state->lane_count == 4) + pixel_rate = max(432000, pixel_rate); + + return pixel_rate; +} + /* compute the max rate for new configuration */ static int ilk_max_pixel_rate(struct drm_atomic_state *state) { @@ -10286,9 +10307,9 @@ static int ilk_max_pixel_rate(struct drm_atomic_state *state) pixel_rate = ilk_pipe_pixel_rate(crtc_state); - /* pixel rate mustn't exceed 95% of cdclk with IPS on BDW */ - if (IS_BROADWELL(dev_priv) && crtc_state->ips_enabled) - pixel_rate = DIV_ROUND_UP(pixel_rate * 100, 95); + if (IS_BROADWELL(dev_priv)) + pixel_rate = bdw_adjust_min_pipe_pixel_rate(crtc_state, + pixel_rate); intel_state->min_pixclk[i] = pixel_rate; }