From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukas Wunner Subject: Re: [PATCH v3 3/8] drm/fb_helper: Introduce hotplug_suspend/resume() Date: Mon, 6 Aug 2018 21:34:57 +0200 Message-ID: <20180806193457.GA7028@wunner.de> References: <20180731003954.19962-1-lyude@redhat.com> <20180731003954.19962-4-lyude@redhat.com> <20180806084322.GK3008@phenom.ffwll.local> <4e72a10062166d646ebd3eb28b6c186d4c00a63f.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <4e72a10062166d646ebd3eb28b6c186d4c00a63f.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: nouveau-bounces-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org Sender: "Nouveau" To: Lyude Paul Cc: David Airlie , nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Daniel Vetter List-Id: nouveau.vger.kernel.org T24gTW9uLCBBdWcgMDYsIDIwMTggYXQgMDM6MTU6MzFQTSAtMDQwMCwgTHl1ZGUgUGF1bCB3cm90 ZToKPiBZb3UgZGlkIG1lbnRpb24gaW4gdGhlIHJldmlldyBvZiBvbmUgb2YgbXkgb3RoZXIgcGF0 Y2hlcyB0aGF0IHdlIHNob3VsZCBhdm9pZAo+IGRpc2FibGluZyBwb2xsaW5nIGR1cmluZyBydW50 aW1lIHN1c3BlbmQsIGFuZCB5b3UncmUgZGVmaW5pdGVseSByaWdodC4gSSBmZWVsCj4gYSBiaXQg c2lsbHkgZm9yIG5vdCByZW1lbWJlcmluZyB0aGF0IHNpbmNlIEkgd2FzIHRoZSBvbmUgd2hvIG1h ZGUgaXQgc28gdGhhdAo+IGk5MTUgZG9lcyBwb2xsaW5nIGluIHJ1bnRpbWUgc3VzcGVuZCBmb3Ig Y2hpcHMgd2l0aG91dCBSUE0gSFBEIGRldGVjdGlvbiBpbgo+IHRoZSBmaXJzdCBwbGFjZSBiZWNh dXNlIGl0IHdhcyBjYXVzaW5nIHBlb3BsZSdzIGRpc3BsYXlzIG5vdCB0byBjb21lIHVwIG9uCj4g dmx2Li4uCj4gQW55d2F5OiBJIHRoaW5rIGlmIHdlIGp1c3QgbGVhdmUgb3V0cHV0IHBvbGxpbmcg ZW5hYmxlZCBkdXJpbmcgcnVudGltZSBzdXNwZW5kCj4gdGhhdCBtaWdodCBhY3R1YWxseSBmaXgg YWxsIG9mIHRoZSBmYl9oZWxwZXIgbG9ja2luZyBpc3N1ZXMgc2luY2Ugd2Ugd29uJ3QKPiBuZWVk IHRvIHdhaXQgb24gYW55IG9mIHRoZSBvdXRwdXQgcG9sbCB3b3JrZXJzIHRvIGZpbmlzaCwgYXQg bGVhc3QgSSB0aGluayBpdAo+IHNob3VsZDogSSdsbCBjb25maXJtIHRoaXMgd2hlbiBJIGdldCBp bnRvIHRoZSBvZmZpY2UKClF1b3RoIEltcmUgRGVhazoKCiAgICJJbiBpOTE1IHBvbGxpbmcgaXMg b24gZHVyaW5nIHJ1bnRpbWUgc3VzcGVuZCBvbmx5IGlmIHRoZXJlIGFyZSBvdXRwdXRzCiAgICB3 aXRob3V0IGhvdHBsdWcgaW50ZXJydXB0IHN1cHBvcnQuIEEgc3BlY2lhbCBjYXNlIGlzIHdoZW4g YW4gb3V0cHV0IGhhcwogICAgd29ya2luZyBIUEQgaW50ZXJydXB0cyB3aGVuIGluIEQwLCBidXQg bm8gaW50ZXJydXB0cyB3aGVuIHJ1bnRpbWUKICAgIHN1c3BlbmRlZC4gRm9yIHRoZXNlIHdlIHN0 YXJ0IHBvbGxpbmcgKGZyb20gYSBzY2hlZHVsZWQgd29yaykgaW4gdGhlCiAgICBydW50aW1lIHN1 c3BlbmQgaG9vayBhbmQgc3RvcCBpdCBpbiB0aGUgcnVudGltZSByZXN1bWUgaG9vayAoYWdhaW4g ZnJvbQogICAgYSBzY2hlZHVsZWQgd29yaykuIgogICAgaHR0cHM6Ly9sa21sLm9yZy9sa21sLzIw MTgvMi8xMi8zMzAKCm5vdXZlYXUgb25seSB1c2VzIHJ1bnRpbWUgUE0gb24gZGlzY3JldGUgR1BV cyBpbiBkdWFsIEdQVSBsYXB0b3BzLgpSZXN1bWluZyB0aGUgR1BVIGZyb20gRDNjb2xkIHRvIEQw IGV2ZXJ5IGZldyBzZWNvbmRzIHRvIHBvbGwgdGhlCm91dHB1dHMgd291bGQgd2FzdGUgdG9vIG11 Y2ggcG93ZXIgb24gc3VjaCBtYWNoaW5lcy4KClRoZSBxdWVzdGlvbiBpcywgd2h5IGlzIHBvbGxp bmcgcnVubmluZyBhdCBhbGwsIHNpbmNlIGFsbCBtb2Rlcm4KbGFwdG9wcyBoYXZlIEhQRC1jYXBh YmxlIHBvcnRzIHN1Y2ggYXMgRFA/CgpUaGFua3MsCgpMdWthcwpfX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fXwpOb3V2ZWF1IG1haWxpbmcgbGlzdApOb3V2ZWF1 QGxpc3RzLmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWls bWFuL2xpc3RpbmZvL25vdXZlYXUK 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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 A5EDDC4646D for ; Mon, 6 Aug 2018 19:35:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 352A821A5E for ; Mon, 6 Aug 2018 19:35:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 352A821A5E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732377AbeHFVpe (ORCPT ); Mon, 6 Aug 2018 17:45:34 -0400 Received: from bmailout1.hostsharing.net ([83.223.95.100]:39409 "EHLO bmailout1.hostsharing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727585AbeHFVpe (ORCPT ); Mon, 6 Aug 2018 17:45:34 -0400 Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.hostsharing.net", Issuer "COMODO RSA Domain Validation Secure Server CA" (not verified)) by bmailout1.hostsharing.net (Postfix) with ESMTPS id 3C74D3004D18E; Mon, 6 Aug 2018 21:34:58 +0200 (CEST) Received: by h08.hostsharing.net (Postfix, from userid 100393) id 01E102FE97; Mon, 6 Aug 2018 21:34:57 +0200 (CEST) Date: Mon, 6 Aug 2018 21:34:57 +0200 From: Lukas Wunner To: Lyude Paul Cc: Daniel Vetter , David Airlie , nouveau@lists.freedesktop.org, Karol Herbst , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v3 3/8] drm/fb_helper: Introduce hotplug_suspend/resume() Message-ID: <20180806193457.GA7028@wunner.de> References: <20180731003954.19962-1-lyude@redhat.com> <20180731003954.19962-4-lyude@redhat.com> <20180806084322.GK3008@phenom.ffwll.local> <4e72a10062166d646ebd3eb28b6c186d4c00a63f.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4e72a10062166d646ebd3eb28b6c186d4c00a63f.camel@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 06, 2018 at 03:15:31PM -0400, Lyude Paul wrote: > You did mention in the review of one of my other patches that we should avoid > disabling polling during runtime suspend, and you're definitely right. I feel > a bit silly for not remembering that since I was the one who made it so that > i915 does polling in runtime suspend for chips without RPM HPD detection in > the first place because it was causing people's displays not to come up on > vlv... > Anyway: I think if we just leave output polling enabled during runtime suspend > that might actually fix all of the fb_helper locking issues since we won't > need to wait on any of the output poll workers to finish, at least I think it > should: I'll confirm this when I get into the office Quoth Imre Deak: "In i915 polling is on during runtime suspend only if there are outputs without hotplug interrupt support. A special case is when an output has working HPD interrupts when in D0, but no interrupts when runtime suspended. For these we start polling (from a scheduled work) in the runtime suspend hook and stop it in the runtime resume hook (again from a scheduled work)." https://lkml.org/lkml/2018/2/12/330 nouveau only uses runtime PM on discrete GPUs in dual GPU laptops. Resuming the GPU from D3cold to D0 every few seconds to poll the outputs would waste too much power on such machines. The question is, why is polling running at all, since all modern laptops have HPD-capable ports such as DP? Thanks, Lukas