From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 33A49C6FD1D for ; Tue, 21 Mar 2023 13:45:09 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9C2BB10E7AD; Tue, 21 Mar 2023 13:45:08 +0000 (UTC) Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4582110E0FA for ; Tue, 21 Mar 2023 13:45:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1679406306; x=1710942306; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=Rob6XdmAWfcEGIheovff08GtLY/K2T5/7E3fRv2cYZM=; b=PJC+BTaCAhgZvCvnmIekGeGmPdaTrM6ORZzvtZNFGznTKWkSpAX4xseT PuCcPrGZX/0IeqDQtMAP0f37tOVztJUXudnL/nSP81p4w2RUCmriT3Qv3 8kdun3g85LA1c2Kzh2TDdXk3CIXLJQhe8tpOgf/qTccX5FOoB+4Fnv2l3 DUofIlwCktNBp4mA8a46CEnm1F+IoxL8O9Mozk4+ha4+Y1W1exYDUyh0+ tu71w8Pt7TImc6Mw1lsL2xljz89863yuRyM0vdxkiPuF6rx3MdcD58iN1 NoLAM0kH5AQzeQT2FUmmtQTNOvTK/o5D8VRqSWvnDINeC0GX6oTJ0HNlz w==; X-IronPort-AV: E=McAfee;i="6600,9927,10656"; a="336446351" X-IronPort-AV: E=Sophos;i="5.98,279,1673942400"; d="scan'208";a="336446351" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Mar 2023 06:45:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10656"; a="683880799" X-IronPort-AV: E=Sophos;i="5.98,279,1673942400"; d="scan'208";a="683880799" Received: from ideak-desk.fi.intel.com ([10.237.72.58]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Mar 2023 06:45:04 -0700 Date: Tue, 21 Mar 2023 15:45:01 +0200 From: Imre Deak To: "Kahola, Mika" Message-ID: References: <20230316131724.359612-1-imre.deak@intel.com> <20230316131724.359612-2-imre.deak@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Intel-gfx] [PATCH 01/14] drm/i915/tc: Abort DP AUX transfer on a disconnected TC port X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: imre.deak@intel.com Cc: Chris Chiu , "intel-gfx@lists.freedesktop.org" Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, Mar 21, 2023 at 01:09:41PM +0200, Kahola, Mika wrote: > > -----Original Message----- > > From: Intel-gfx On Behalf Of Imre > > Deak > > Sent: Thursday, March 16, 2023 3:17 PM > > To: intel-gfx@lists.freedesktop.org > > Cc: Chris Chiu > > Subject: [Intel-gfx] [PATCH 01/14] drm/i915/tc: Abort DP AUX transfer on a > > disconnected TC port > > > > On TC ports the 4ms AUX timeout combined with the 5 * 32 retry attempts > > during DPCD accesses adds a 640ms delay to each access if the sink is > > disconnected. This in turn slows down a modeset during which the sink is > > disconnected (for instance a disabling modeset). > > > > Prevent the above delay by aborting AUX transfers on a TC port with a > > disconnected sink. > > > > The DP 1.4a link CTS (4.2.1.5 Source Device Inactive HPD / Inactive AUX > > Test") also requires not to initiate AUX transfers on disconnected DP ports in > > general, however this patch doesn't change the behavior on non-TC ports, > > leaving that for a follow-up. > > > > Reported-and-tested-by: Chris Chiu > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8279 > > Signed-off-by: Imre Deak > > --- > > drivers/gpu/drm/i915/display/intel_dp_aux.c | 15 +++++++++++++-- > > drivers/gpu/drm/i915/display/intel_tc.c | 15 +++++++++++---- > > drivers/gpu/drm/i915/display/intel_tc.h | 1 + > > 3 files changed, 25 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c > > b/drivers/gpu/drm/i915/display/intel_dp_aux.c > > index 96967e21c94c2..eb07dc5d87099 100644 > > --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c > > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c > > @@ -205,8 +205,19 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp, > > for (i = 0; i < ARRAY_SIZE(ch_data); i++) > > ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i); > > > > - if (is_tc_port) > > + if (is_tc_port) { > > intel_tc_port_lock(dig_port); > > + /* > > + * Abort transfers on a disconnected port as required by > > + * DP 1.4a link CTS 4.2.1.5, also avoiding the long AUX > > + * timeouts that would otherwise happen. > > + * TODO: abort the transfer on non-TC ports as well. > > + */ > > + if (!intel_tc_port_connected_locked(&dig_port->base)) { > > + ret = -ENXIO; > > TC port being a physical object this error code could be ENODEV as well, right? The meaning of either error code is not defined precisely, but I interpreted ENXIO as a - temporary - error/non-presence of the remote device downstream of the port. There is another driver returning ENXIO for the same case. > Anyway, patch looks ok to me. > > Reviewed-by: Mika Kahola > > > + goto out_unlock; > > + } > > + } > > > > aux_domain = intel_aux_power_domain(dig_port); > > > > @@ -367,7 +378,7 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp, > > > > intel_pps_unlock(intel_dp, pps_wakeref); > > intel_display_power_put_async(i915, aux_domain, aux_wakeref); > > - > > +out_unlock: > > if (is_tc_port) > > intel_tc_port_unlock(dig_port); > > > > diff --git a/drivers/gpu/drm/i915/display/intel_tc.c > > b/drivers/gpu/drm/i915/display/intel_tc.c > > index f45328712bff1..050f998284592 100644 > > --- a/drivers/gpu/drm/i915/display/intel_tc.c > > +++ b/drivers/gpu/drm/i915/display/intel_tc.c > > @@ -768,16 +768,23 @@ void intel_tc_port_sanitize_mode(struct > > intel_digital_port *dig_port) > > * connected ports are usable, and avoids exposing to the users objects they > > * can't really use. > > */ > > +bool intel_tc_port_connected_locked(struct intel_encoder *encoder) { > > + struct intel_digital_port *dig_port = enc_to_dig_port(encoder); > > + struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev); > > + > > + drm_WARN_ON(&i915->drm, !intel_tc_port_ref_held(dig_port)); > > + > > + return tc_port_live_status_mask(dig_port) & BIT(dig_port->tc_mode); } > > + > > bool intel_tc_port_connected(struct intel_encoder *encoder) { > > struct intel_digital_port *dig_port = enc_to_dig_port(encoder); > > bool is_connected; > > > > intel_tc_port_lock(dig_port); > > - > > - is_connected = tc_port_live_status_mask(dig_port) & > > - BIT(dig_port->tc_mode); > > - > > + is_connected = intel_tc_port_connected_locked(encoder); > > intel_tc_port_unlock(dig_port); > > > > return is_connected; > > diff --git a/drivers/gpu/drm/i915/display/intel_tc.h > > b/drivers/gpu/drm/i915/display/intel_tc.h > > index d54082e2d5e8d..93813056043a5 100644 > > --- a/drivers/gpu/drm/i915/display/intel_tc.h > > +++ b/drivers/gpu/drm/i915/display/intel_tc.h > > @@ -17,6 +17,7 @@ bool intel_tc_port_in_dp_alt_mode(struct > > intel_digital_port *dig_port); bool intel_tc_port_in_legacy_mode(struct > > intel_digital_port *dig_port); > > > > bool intel_tc_port_connected(struct intel_encoder *encoder); > > +bool intel_tc_port_connected_locked(struct intel_encoder *encoder); > > > > u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port); > > u32 intel_tc_port_get_pin_assignment_mask(struct intel_digital_port > > *dig_port); > > -- > > 2.37.1 >