From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 1/2] vga_switcheroo: add power support for windows 10 machines. Date: Mon, 14 Mar 2016 11:02:59 +0100 Message-ID: <20160314100259.GP14170@phenom.ffwll.local> References: <1457504045-12738-1-git-send-email-airlied@gmail.com> <2736217.utxPzJExd5@vostro.rjw.lan> <20160311105815.GS1796@lahna.fi.intel.com> <2759763.dR5D0KopkA@vostro.rjw.lan> <20160314094335.GE1796@lahna.fi.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Dave Airlie Cc: "Rafael J. Wysocki" , Linux PCI , "linux-pm@vger.kernel.org" , "Rafael J. Wysocki" , Linux Kernel Mailing List , dri-devel , ACPI Devel Maling List , Mika Westerberg List-Id: linux-acpi@vger.kernel.org T24gTW9uLCBNYXIgMTQsIDIwMTYgYXQgMDc6NDc6MzlQTSArMTAwMCwgRGF2ZSBBaXJsaWUgd3Jv dGU6Cj4gPgo+ID4+IC0gICAgIGlmIChwY2llX3BvcnRfcnVudGltZV9zdXNwZW5kX2FsbG93ZWQo ZGV2KSkKPiA+PiArICAgICBpZiAocGNpZV9wb3J0X3J1bnRpbWVfc3VzcGVuZF9hbGxvd2VkKGRl dikpIHsKPiA+PiArICAgICAgICAgICAgIHBtX3J1bnRpbWVfYWxsb3coJmRldi0+ZGV2KTsKPiA+ Cj4gPiBQQ0kgZHJpdmVycyB0eXBpY2FsbHkgaGF2ZSBsZWZ0IHRoaXMgZGVjaXNpb24gdXAgdG8g dGhlIHVzZXJzcGFjZS4gSSdtCj4gPiB3b25kZXJpbmcgd2hldGhlciBpdCBpcyBnb29kIGlkZWEg dG8gZGV2aWF0ZSBmcm9tIHRoYXQgaGVyZT8gT2YgY291cnNlCj4gPiB0aGlzIGFsbG93cyBpbW1l ZGlhdGUgcG93ZXIgc2F2aW5ncyBidXQgY291bGQgcG90ZW50aWFsbHkgY2F1c2UgcHJvYmxlbXMK PiA+IGFzIHdlbGwuCj4gPgo+IAo+IE5vIGRpc3RybyBoYXMgZXZlciBzaGlwcGVkIHVzZXJzcGFj ZSB0byBkbyB0aGlzLCBJIHJlYWxseSB0aGluayB0aGlzCj4gaXMgYSBiYWQgZGVzaWduLgo+IFdl IGhhdmUgd2FzdGVkIGNvdW50bGVzcyB3YXR0cyBvZiBwb3dlciBvbiB0aGlzIHN0dXBpZCBpZGVh IHRoYXQgcGVvcGxlIHdpbGwKPiBydW4gcG93ZXJ0b3AsIG9ubHkgYSBmZXcgcGVvcGxlIGluIHRo ZSB3b3JsZCBydW4gcG93ZXJ0b3AsIGxvdHMgb2YKPiBwZW9wbGUgdXNlIExpbnV4Lgo+IAo+IFRo ZSBrZXJuZWwgc2hvdWxkIHBvd2VyIHN0dWZmIGRvd24gbm90IHdhaXQgZm9yIHRoZSB1c2VyIHRv IHJ1biBwb3dlcnRvcCwKPiBBdCBsZWFzdCBmb3IgdGhlIEdQVSBpdCdzIGluIHRoZSBhcmVhIG9m IDhXIG9mIHBvd2VyLCBhbmQgSSd2ZSBnb3QgdGhlCj4gR1BVIGRyaXZlcnMgZG9pbmcgdGhpcyB0 aGVtc2VsdmVzLAo+IAo+IEkgY291bGQgaGF2ZSB0aGUgR1BVIGRyaXZlciBjYWxsIHJ1bnRpbWUg YWxsb3cgZm9yIGl0J3MgaG9zdCBicmlkZ2UgSSBzdXBwb3NlLAo+IGlmIHdlIGluc2lzdCBvbiB0 aGUgdXNlcnNwYWNlIGNhcmVzLCBidXQgSSdkIHByZWZlciBub3QgZG9pbmcgc28uCgpZZXMsIGZ1 bGx5IGFncmVlZC4gUnVudGltZSBQTSB0aGF0J3Mgbm90IGVuYWJsZWQgYnkgZGVmYXVsdCBpcyB1 c2VsZXNzLApzaW5jZSBubyBvbmUgcnVucyBwb3dlcnRvcCwgd2hpY2ggYWxzbyBtZWFucyBpdCdz IGJ1Z2d5IGJlY2F1c2Ugbm8gb25lCnRlc3RzIGl0LiBOb3QgZW5hYmxpbmcgcG93ZXIgc2F2aW5n IGZlYXR1cmVzIGJ5IGRlZmF1bHQgaXMgaW1vIGp1c3QgYSBsYW1lCmV4Y3VzZS4gU2hpdCBiZXR0 ZXIganVzdCB3b3JrLCBhbmQgdHVuZWFibGVzIHNob3VsZCBvbmx5IGV4cG9zZWQgaWYKdGhlcmUn cyBhIHJlYWwgcmVhc29uIHdoeSBhdXRvdHVuaW5nIGlzIGluZmVhc2libGUuIEUuZy4gd2UgYXV0 by1yYW1wIHRoZQpncHUgY2xvY2sgZG93bi91cCBpbiBpOTE1IGluIHNvZnR3YXJlIHRvIGNvbXBl bnNhdGUgZm9yIHNvbWUgb2YgdGhlCnNpbGxpbmVzcyBpbiBob3cgdGhlIGh3IGRvZXMgaXQgYWxv bmUuIEFuZCB0aGUgc3lzZnMgdHVuYWJsZXMgYXJlIG1vc3RseQpqdXN0IHRvIG1ha2UgYmVuY2ht YXJraW5nICh3aGVyZSBzbG93ZXIsIGJ1dCB3aXRob3V0IGFueSB0aGVybWFsCnRocm90dGxpbmcp IGlzIHNvbWV0aW1lcyBwcmVmZXJyZWQuCgpBbmQgeWVzIGk5MTUgaGFzbid0IGVuYWJsZWQgcnBt IHlldCBieSBkZWZhdWx0IGJlY2F1c2UgdGhlcmUncyBidWdzIGxlZnQKOigKLURhbmllbAotLSAK RGFuaWVsIFZldHRlcgpTb2Z0d2FyZSBFbmdpbmVlciwgSW50ZWwgQ29ycG9yYXRpb24KaHR0cDov L2Jsb2cuZmZ3bGwuY2gKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX18KZHJpLWRldmVsIG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Au b3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRl dmVsCg== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f66.google.com ([74.125.82.66]:34725 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755481AbcCNKCN (ORCPT ); Mon, 14 Mar 2016 06:02:13 -0400 Received: by mail-wm0-f66.google.com with SMTP id p65so14231147wmp.1 for ; Mon, 14 Mar 2016 03:02:13 -0700 (PDT) Date: Mon, 14 Mar 2016 11:02:59 +0100 From: Daniel Vetter To: Dave Airlie Cc: Mika Westerberg , "linux-pm@vger.kernel.org" , Linux PCI , "Rafael J. Wysocki" , "Rafael J. Wysocki" , Linux Kernel Mailing List , dri-devel , ACPI Devel Maling List Subject: Re: [PATCH 1/2] vga_switcheroo: add power support for windows 10 machines. Message-ID: <20160314100259.GP14170@phenom.ffwll.local> References: <1457504045-12738-1-git-send-email-airlied@gmail.com> <2736217.utxPzJExd5@vostro.rjw.lan> <20160311105815.GS1796@lahna.fi.intel.com> <2759763.dR5D0KopkA@vostro.rjw.lan> <20160314094335.GE1796@lahna.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-pci-owner@vger.kernel.org List-ID: On Mon, Mar 14, 2016 at 07:47:39PM +1000, Dave Airlie wrote: > > > >> - if (pcie_port_runtime_suspend_allowed(dev)) > >> + if (pcie_port_runtime_suspend_allowed(dev)) { > >> + pm_runtime_allow(&dev->dev); > > > > PCI drivers typically have left this decision up to the userspace. I'm > > wondering whether it is good idea to deviate from that here? Of course > > this allows immediate power savings but could potentially cause problems > > as well. > > > > No distro has ever shipped userspace to do this, I really think this > is a bad design. > We have wasted countless watts of power on this stupid idea that people will > run powertop, only a few people in the world run powertop, lots of > people use Linux. > > The kernel should power stuff down not wait for the user to run powertop, > At least for the GPU it's in the area of 8W of power, and I've got the > GPU drivers doing this themselves, > > I could have the GPU driver call runtime allow for it's host bridge I suppose, > if we insist on the userspace cares, but I'd prefer not doing so. Yes, fully agreed. Runtime PM that's not enabled by default is useless, since no one runs powertop, which also means it's buggy because no one tests it. Not enabling power saving features by default is imo just a lame excuse. Shit better just work, and tuneables should only exposed if there's a real reason why autotuning is infeasible. E.g. we auto-ramp the gpu clock down/up in i915 in software to compensate for some of the silliness in how the hw does it alone. And the sysfs tunables are mostly just to make benchmarking (where slower, but without any thermal throttling) is sometimes preferred. And yes i915 hasn't enabled rpm yet by default because there's bugs left :( -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch