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 X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 091ACC34026 for ; Tue, 18 Feb 2020 17:15:57 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D06C0208C4 for ; Tue, 18 Feb 2020 17:15:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=poorly.run header.i=@poorly.run header.b="dPQaJG3G" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D06C0208C4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=poorly.run Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3A7AF6E351; Tue, 18 Feb 2020 17:15:56 +0000 (UTC) Received: from mail-yb1-xb42.google.com (mail-yb1-xb42.google.com [IPv6:2607:f8b0:4864:20::b42]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1147D6E351 for ; Tue, 18 Feb 2020 17:15:55 +0000 (UTC) Received: by mail-yb1-xb42.google.com with SMTP id w17so10848707ybm.1 for ; Tue, 18 Feb 2020 09:15:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=poorly.run; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=ZsHnnQknMDvDZ+Jc5/5zgbiOYf9jw7tORlt8ck31SXk=; b=dPQaJG3GBpeqjal0fOhHj5+raNQNspr8XTNOf6mOH4wTSUBAYVd5Fc9QicCv4U1jrR 0o0oR53vgXv7cjNUc2JSyrXrcvXOgEEyruSgQrMJer4AUhwC3MUUu7CPT3BOb7Gjg0e1 3GVqtNrq5/PnLiN7QQi+wz7tcNIoyyO0ggjkYcBT75K+3FTehmQwgrhN2NJD3zitawAi +iqxHlgNBGpz7Z0Lb+f5/Fri90Mu+953a/tDkv0rbkUMX0iBd9uOQkNnTPp+TW0SCyru M/IFsZHc9rUI2WLz1upsXkVIb43Bzdbqwtxaft9faOC8BZJTiiWgq5Vr5/pqRn6PCWiJ Xwrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=ZsHnnQknMDvDZ+Jc5/5zgbiOYf9jw7tORlt8ck31SXk=; b=Aqj81Mxrrb/i2C+0UmI1rDkiriB8+pXt+Ze+qRXbnfPy9vm+Ge6cTSZcN2A+pjz9qE DYqP5ZQLmIBFbFfgAIX4KtKzpAcGggpDJwfuTDlqiKWLUTTLNoYjl2JpMfQ7cka4mniW jw0vvtpgHo+gijbQMvK+cjf72mcMU9J2Tkm4y9PnYiqhgJrT8SsS51jCaOGMu9G4vZFf euB6Ent6fdLdNGCvubEkKMdoZGR4wrlWoliE+qPT9ieZ4F79PEFX+Viw2+WbUn4vraAz YbbOzHTQMU84j1uRl8dhTB/Ub9P94gXhVtnmCxF9TXABwYU/YmbveIyehgjsY65olU9l J1mQ== X-Gm-Message-State: APjAAAXxgJVubsj6PC7HnAFduWVT/i+k7SrqcJQjFPHbvv9v1NeiDNnV h7+8R4ysdK5/tXqPltldfQOvDA== X-Google-Smtp-Source: APXvYqyVNOAZyTiQD5E5/HmEBSOb1LwYLPt17D5EYDdeNBLE1BiEOKT2b6DolT7cvKCmzCevEf3DWA== X-Received: by 2002:a25:38c1:: with SMTP id f184mr18282792yba.522.1582046154153; Tue, 18 Feb 2020 09:15:54 -0800 (PST) Received: from localhost ([2620:0:1013:11:1e1:4760:6ce4:fc64]) by smtp.gmail.com with ESMTPSA id s130sm1903171ywg.11.2020.02.18.09.15.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Feb 2020 09:15:53 -0800 (PST) Date: Tue, 18 Feb 2020 12:15:22 -0500 From: Sean Paul To: "Lin, Wayne" Subject: Re: [PATCH 3/3] drm/dp_mst: Remove single tx msg restriction. Message-ID: <20200218171522.GF253734@art_vandelay> References: <20200213211523.156998-1-sean@poorly.run> <20200213211523.156998-4-sean@poorly.run> <20200218155206.GD253734@art_vandelay> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200218155206.GD253734@art_vandelay> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: David Airlie , Sean Paul , "dri-devel@lists.freedesktop.org" , Sean Paul Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Feb 18, 2020 at 10:52:06AM -0500, Sean Paul wrote: > On Mon, Feb 17, 2020 at 07:08:37AM +0000, Lin, Wayne wrote: > > [AMD Public Use] > > > > > > > > > -----Original Message----- > > > From: Sean Paul > > > Sent: Saturday, February 15, 2020 12:09 AM > > > To: Lin, Wayne > > > Cc: dri-devel@lists.freedesktop.org; lyude@redhat.com; Sean Paul > > > ; Maarten Lankhorst > > > ; Maxime Ripard ; > > > David Airlie > > > Subject: Re: [PATCH 3/3] drm/dp_mst: Remove single tx msg restriction. > > > > > > On Fri, Feb 14, 2020 at 12:58 AM Lin, Wayne wrote: > > > > > > > > [AMD Public Use] > > > > > > > > Hi Paul, > > > > > > > > Thanks for the mail! > > > > > > > > I tried to solve this problem by having restriction on sending one msg at a > > > time due to hub/dock compatibility problems. > > > > From my experience, some branch devices don't handle well on > > > > interleaved replies (Dock from HP I think) > > > > > > Hi Wayne, > > > Hmm, that's interesting, do you have a part number of the failing dock so I can > > > test it? > > > > > Hi Paul, > > > > Sorry but it's been quite a while. I can't exactly tell the part number. > > If I remember correctly, when the specific branch device receives interleaved replies, > > it just doesn't reply to any requests. > > > > > > As the result of that, correct me if I'm wrong, I remember most gpu vendors > > > just send one down request at a time now in windows environment. > > > > I would suggest the original solution :) > > > > > > I can't really say what happens on the Windows side of the world, but I suppose > > > that makes sense if this is a widespread issue with docks. I do worry about the > > > performance hit. > > > > > > If indeed this is a problem, could we ratelimit per branch device instead of > > > globally? Even that would be better than serializing everything. > > > > > Since the problem was because some branch devices can't simultaneously handle > > two replies, I'm afraid that we might still encounter the same problem? > > > > Hi Wayne, > Thanks for clarifying. I'm a bit hesitant to scrap this idea without solid > evidence that this is a common problem. Do you have any hubs around AMD that > you could try my patchset with? Oh, if you can test the set, you'll also need this patch as well :-) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3814,7 +3814,9 @@ static bool drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up, int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : DP_SIDEBAND_MSG_DOWN_REP_BASE; - *mstb = NULL; + if (mstb) + *mstb = NULL; + *seqno = -1; len = min(mgr->max_dpcd_transaction_bytes, 16); > Perhaps we could get some hard data? I'm happy > to test things on my end, but I probably shouldn't just start buying a bunch of > random HP docks in hopes one of them exhibits the issue :) > > To add anecdote to anecdote, everything on my desk seems to work with > interleaved replies. > > Since HDCP spec requires the host to verify each channel's encryption every <2s, > we're going to be increasing the amount of sideband traffic a fair amount, so I > would like to ensure we're doing everything possible to maximize our sideband > bandwidth. > > Sean > > > Thanks! > > > Sean > > > > > > > > > > > Thanks! > > > > > -----Original Message----- > > > > > From: Sean Paul > > > > > Sent: Friday, February 14, 2020 5:15 AM > > > > > To: dri-devel@lists.freedesktop.org > > > > > Cc: lyude@redhat.com; Lin, Wayne ; Sean Paul > > > > > ; Maarten Lankhorst > > > > > ; Maxime Ripard > > > > > ; David Airlie > > > > > Subject: [PATCH 3/3] drm/dp_mst: Remove single tx msg restriction. > > > > > > > > > > From: Sean Paul > > > > > > > > > > Now that we can support multiple simultaneous replies, remove the > > > > > restrictions placed on sending new tx msgs. > > > > > > > > > > This patch essentially just reverts commit > > > > > 5a64967a2f3b ("drm/dp_mst: Have DP_Tx send one msg at a time") > > > now > > > > > that the problem is solved in a different way. > > > > > > > > > > Cc: Wayne Lin > > > > > Signed-off-by: Sean Paul > > > > > --- > > > > > drivers/gpu/drm/drm_dp_mst_topology.c | 14 ++------------ > > > > > include/drm/drm_dp_mst_helper.h | 6 ------ > > > > > 2 files changed, 2 insertions(+), 18 deletions(-) > > > > > > > > > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c > > > > > b/drivers/gpu/drm/drm_dp_mst_topology.c > > > > > index 7e6a82efdfc02..cbf0bb0ddeb84 100644 > > > > > --- a/drivers/gpu/drm/drm_dp_mst_topology.c > > > > > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c > > > > > @@ -1203,8 +1203,6 @@ static int drm_dp_mst_wait_tx_reply(struct > > > > > drm_dp_mst_branch *mstb, > > > > > txmsg->state == DRM_DP_SIDEBAND_TX_SENT) { > > > > > mstb->tx_slots[txmsg->seqno] = NULL; > > > > > } > > > > > - mgr->is_waiting_for_dwn_reply = false; > > > > > - > > > > > } > > > > > out: > > > > > if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) { > > > > > @@ > > > > > -1214,7 +1212,6 @@ static int drm_dp_mst_wait_tx_reply(struct > > > > > drm_dp_mst_branch *mstb, > > > > > } > > > > > mutex_unlock(&mgr->qlock); > > > > > > > > > > - drm_dp_mst_kick_tx(mgr); > > > > > return ret; > > > > > } > > > > > > > > > > @@ -2797,11 +2794,9 @@ static void > > > > > process_single_down_tx_qlock(struct > > > > > drm_dp_mst_topology_mgr *mgr) > > > > > ret = process_single_tx_qlock(mgr, txmsg, false); > > > > > if (ret == 1) { > > > > > /* txmsg is sent it should be in the slots now */ > > > > > - mgr->is_waiting_for_dwn_reply = true; > > > > > list_del(&txmsg->next); > > > > > } else if (ret) { > > > > > DRM_DEBUG_KMS("failed to send msg in q %d\n", ret); > > > > > - mgr->is_waiting_for_dwn_reply = false; > > > > > list_del(&txmsg->next); > > > > > if (txmsg->seqno != -1) > > > > > txmsg->dst->tx_slots[txmsg->seqno] = NULL; > > > @@ > > > > > -2841,8 > > > > > +2836,7 @@ static void drm_dp_queue_down_tx(struct > > > > > drm_dp_mst_topology_mgr *mgr, > > > > > drm_dp_mst_dump_sideband_msg_tx(&p, txmsg); > > > > > } > > > > > > > > > > - if (list_is_singular(&mgr->tx_msg_downq) && > > > > > - !mgr->is_waiting_for_dwn_reply) > > > > > + if (list_is_singular(&mgr->tx_msg_downq)) > > > > > process_single_down_tx_qlock(mgr); > > > > > mutex_unlock(&mgr->qlock); > > > > > } > > > > > @@ -3822,7 +3816,6 @@ static int drm_dp_mst_handle_down_rep(struct > > > > > drm_dp_mst_topology_mgr *mgr) > > > > > mutex_lock(&mgr->qlock); > > > > > txmsg->state = DRM_DP_SIDEBAND_TX_RX; > > > > > mstb->tx_slots[seqno] = NULL; > > > > > - mgr->is_waiting_for_dwn_reply = false; > > > > > mutex_unlock(&mgr->qlock); > > > > > > > > > > wake_up_all(&mgr->tx_waitq); > > > > > @@ -3830,9 +3823,6 @@ static int drm_dp_mst_handle_down_rep(struct > > > > > drm_dp_mst_topology_mgr *mgr) > > > > > return 0; > > > > > > > > > > out_clear_reply: > > > > > - mutex_lock(&mgr->qlock); > > > > > - mgr->is_waiting_for_dwn_reply = false; > > > > > - mutex_unlock(&mgr->qlock); > > > > > if (msg) > > > > > memset(msg, 0, sizeof(struct > > > drm_dp_sideband_msg_rx)); > > > > > out: > > > > > @@ -4670,7 +4660,7 @@ static void drm_dp_tx_work(struct work_struct > > > > > *work) > > > > > struct drm_dp_mst_topology_mgr *mgr = container_of(work, > > > > > struct drm_dp_mst_topology_mgr, tx_work); > > > > > > > > > > mutex_lock(&mgr->qlock); > > > > > - if (!list_empty(&mgr->tx_msg_downq) > > > > > && !mgr->is_waiting_for_dwn_reply) > > > > > + if (!list_empty(&mgr->tx_msg_downq)) > > > > > process_single_down_tx_qlock(mgr); > > > > > mutex_unlock(&mgr->qlock); > > > > > } > > > > > diff --git a/include/drm/drm_dp_mst_helper.h > > > > > b/include/drm/drm_dp_mst_helper.h index > > > 7d0341f94ce1b..fcc30e64c8e7e > > > > > 100644 > > > > > --- a/include/drm/drm_dp_mst_helper.h > > > > > +++ b/include/drm/drm_dp_mst_helper.h > > > > > @@ -619,12 +619,6 @@ struct drm_dp_mst_topology_mgr { > > > > > * &drm_dp_sideband_msg_tx.state once they are queued > > > > > */ > > > > > struct mutex qlock; > > > > > - > > > > > - /** > > > > > - * @is_waiting_for_dwn_reply: indicate whether is waiting for > > > down > > > > > reply > > > > > - */ > > > > > - bool is_waiting_for_dwn_reply; > > > > > - > > > > > /** > > > > > * @tx_msg_downq: List of pending down replies. > > > > > */ > > > > > -- > > > > > Sean Paul, Software Engineer, Google / Chromium OS > > > > -- > > > > Wayne Lin > > -- > > Best regards, > > Wayne Lin > > -- > Sean Paul, Software Engineer, Google / Chromium OS -- Sean Paul, Software Engineer, Google / Chromium OS _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel