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From: Artur Petrosyan <Arthur.Petrosyan@synopsys.com>
To: Doug Anderson <dianders@chromium.org>
Cc: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>,
	Felipe Balbi <felipe.balbi@linux.intel.com>,
	"heiko@sntech.de" <heiko@sntech.de>,
	"Alan Stern" <stern@rowland.harvard.edu>,
	"amstan@chromium.org" <amstan@chromium.org>,
	"linux-rockchip@lists.infradead.org" 
	<linux-rockchip@lists.infradead.org>,
	William Wu <william.wu@rock-chips.com>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	Stefan Wahren <stefan.wahren@i2se.com>,
	Randy Li <ayaka@soulik.info>,
	"zyw@rock-chips.com" <zyw@rock-chips.com>,
	"mka@chromium.org" <mka@chromium.org>,
	"ryandcase@chromium.org" <ryandcase@chromium.org>,
	Amelie Delaunay <amelie.delaunay@st.com>,
	"jwerner@chromium.org" <jwerner@chromium.org>,
	"dinguyen@opensource.altera.com" <dinguyen@opensource.altera.com>,
	"Elaine Zhang" <zhangqing@rock-chips.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/5] usb: dwc2: bus suspend/resume for hosts with DWC2_POWER_DOWN_PARAM_NONE
Date: Tue, 7 May 2019 07:26:59 +0000
Message-ID: <SN1PR12MB2431A37C761DA0BAAEF45F30A7310@SN1PR12MB2431.namprd12.prod.outlook.com> (raw)
In-Reply-To: <CAD=FV=XzsKe5n_ThcrByW79UznpkmHf0YNRNKH8G3eFtUSsYZQ@mail.gmail.com>

On 5/3/2019 19:04, Doug Anderson wrote:
> Hi,
> 
> On Fri, May 3, 2019 at 1:20 AM Artur Petrosyan
> <Arthur.Petrosyan@synopsys.com> wrote:
>>
>> On 5/1/2019 05:57, Doug Anderson wrote:
>>> Hi,
>>>
>>> On Mon, Apr 29, 2019 at 11:06 PM Artur Petrosyan
>>> <Arthur.Petrosyan@synopsys.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> On 4/29/2019 21:34, Doug Anderson wrote:
>>>>> Hi,
>>>>>
>>>>> On Mon, Apr 29, 2019 at 1:43 AM Artur Petrosyan
>>>>> <Arthur.Petrosyan@synopsys.com> wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> On 4/18/2019 04:15, Douglas Anderson wrote:
>>>>>>> This is an attempt to rehash commit 0cf884e819e0 ("usb: dwc2: add bus
>>>>>>> suspend/resume for dwc2") on ToT.  That commit was reverted in commit
>>>>>>> b0bb9bb6ce01 ("Revert "usb: dwc2: add bus suspend/resume for dwc2"")
>>>>>>> because apparently it broke the Altera SOCFPGA.
>>>>>>>
>>>>>>> With all the changes that have happened to dwc2 in the meantime, it's
>>>>>>> possible that the Altera SOCFPGA will just magically work with this
>>>>>>> change now.  ...and it would be good to get bus suspend/resume
>>>>>>> implemented.
>>>>>>>
>>>>>>> This change is a forward port of one that's been living in the Chrome
>>>>>>> OS 3.14 kernel tree.
>>>>>>>
>>>>>>> Signed-off-by: Douglas Anderson <dianders@chromium.org>
>>>>>>> ---
>>>>>>> This patch was last posted at:
>>>>>>>
>>>>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__lkml.kernel.org_r_1446237173-2D15263-2D1-2Dgit-2Dsend-2Demail-2Ddianders-40chromium.org&d=DwIDAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=9hPBFKCJ_nBjJhGVrrlYOeOQjP_HlVzYqrC_D7niMJI&m=MMfe-4lZePyty6F5zfQ54kiYGuJWNulyRat944LkOsc&s=nExFpAPP_0plZfO5LMG1B-mqt1vyCvE35elVcyVgs8Y&e=
>>>>>>>
>>>>>>> ...and appears to have died the death of silence.  Maybe it could get
>>>>>>> some bake time in linuxnext if we can't find any proactive testing?
>>>>>>>
>>>>>>> I will also freely admit that I don't know tons about the theory
>>>>>>> behind this patch.  I'm mostly just re-hashing the original commit
>>>>>>> from Kever that was reverted since:
>>>>>>> * Turning on partial power down on rk3288 doesn't "just work".  I
>>>>>>>       don't get hotplug events.  This is despite dwc2 auto-detecting that
>>>>>>>       we are power optimized.
>>>>>> What do you mean by doesn't "just work" ? It seem to me that even after
>>>>>> adding this patch you don't get issues fixed.
>>>>>> You mention that you don't get the hotplug events. Please provide dwc2
>>>>>> debug logs and register dumps on this issue.
>>>>>
>>>>> I mean that partial power down in the currently upstream driver
>>>>> doesn't work.  AKA: if I turn on partial power down in the upstream
>>>>> driver then hotplug events break.  I can try to provide some logs.  On
>>>>> what exact version of the code do you want logs?  Just your series?
>>>>> Just my series?  Mainline?  Some attempt at combining both series?  As
>>>>> I said things seem to sorta work with the combined series.  I can try
>>>>> to clarify if that's the series you want me to test with.  ...or I can
>>>>> wait for your next version?
>>>> As I said this patch doesn't fix the issue with hotplug. With this patch
>>>> or without the hotplug behaves as it was. I have tested it on our setup.
>>>>
>>>> Have you debugged your patch? Does it make any difference on your setup
>>>> ? Does it fix the issue with hotplug?
>>>
>>> I think we're still not taking on the same page.
>>>
>>> My patch makes no attempt to make partial power down mode work.  My
>>> patch attempts to make things work a little better when using
>>> DWC2_POWER_DOWN_PARAM_NONE.  There is no use testing my patch with
>>> partial power down as it shouldn't have any impact there.
>>>
>>>
>>>>> I am by no means an expert on dwc2, but an assumption made in my patch
>>>>> is that even cores that can't support partial power down can still
>>>>> save some amount of power when hcd_suspend is called.
>>>> Have you tried to debug dwc2 with power_down == DWC2_POWER_DOWN_PARAM_NONE ?
>>>>>
>>>>> Some evidence that this should be possible: looking at mainline Linux
>>>>> and at dwc2_port_suspend(), I see:
>>>>>
>>>>> * It is currently called even when we have DWC2_POWER_DOWN_PARAM_NONE
>>>> Currently (without your and my patches) (looking at mainline Linux) the
>>>> function dwc2_port_suspend() is called anyway because its call is issued
>>>> by the system. But it performs entering to suspend only in case of
>>>> DWC2_POWER_DOWN_PARAM_PARTIAL.
>>>>
>>>> This is not an assumption. What I am pointing out is based on debugging
>>>> and before making assumptions without debugging for me seems not ok.
>>>>
>>>> Currently without your patch and without my patches. In the
>>>> dwc2_port_suspend() it will enter to suspend only in case that
>>>> power_down == DWC2_POWER_DOWN_PARAM_PARTIAL. Because if you look at the
>>>> code more carefully you will see
>>>>
>>>>           if (hsotg->params.power_down != DWC2_POWER_DOWN_PARAM_PARTIAL)
>>>>                   goto skip_power_saving;
>>>>
>>>> This says if power_down is not DWC2_POWER_DOWN_PARAM_PARTIAL then skip
>>>> power saving.
>>>>
>>>> So but after your patch. If power_down is DWC2_POWER_DOWN_PARAM_NONE it
>>>> tries to suspend.
>>>
>>> We must be looking at different code.  I'm looking at Linux's tree, AKA:
>>>
>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_torvalds_linux.git_tree_drivers_usb_dwc2_hcd.c-23n3488&d=DwIFaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=9hPBFKCJ_nBjJhGVrrlYOeOQjP_HlVzYqrC_D7niMJI&m=IWkDOOGTr0q-H1piDv2KOZe_Hnrz18g6rXFx-DsTuv4&s=AHu2iOKkybliRGtIfN7cF5p070UdvUKTYJsyAKYojis&e=
>> Here you are looking at the old code. After that there are several of
>> changes related to suspend/resume functions.
> 
> In my email, see that I said I actually checked out mainline kernel
> (and I gave you the exact version: "v5.1-rc7-5-g83a50840e72a") and
> added printouts in dwc2_port_suspend() next to where it set HPRT0_SUSP
> and PCGCTL_STOPPCLK in dwc2_port_suspend().
I was talking about your patch which edits _dwc2_hcd_suspend() function.
What dwc2_port_suspend() implements for the hibernation or partial power 
down I have not tested. It is a different implementation.
> 
> [  454.906364] dwc2 ff540000.usb: I'm setting HPRT0_SUSP
> [  454.906367] dwc2 ff540000.usb: I'm setting PCGCTL_STOPPCLK
> 
> The version "v5.1-rc7-5-g83a50840e72a" is not old code.
> 
> 
>> This is the link to the code with changes. Latest version of those
>> functions.
>>
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_torvalds_linux.git_tree_drivers_usb_dwc2_hcd.c-23n4489&d=DwIFaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=9hPBFKCJ_nBjJhGVrrlYOeOQjP_HlVzYqrC_D7niMJI&m=4lskGlSdN5lp0MXVy1SP0zxzFtbPMSUoQKQzLLmfoOg&s=A-ikUNQklzouItTOQB078WrOiMcfCqgw8sBgLFwtyTU&e=
>>
>> Your changes are sitting on that latest version of code. Not the old
>> version of it.
> 
> You are pointing me at _dwc2_hcd_suspend() whereas I pointed at
> dwc2_port_suspend().  Why?
Because your patch is editing _dwc2_hcd_suspend().
> 
> I am saying that dwc2_port_suspend() _does_ set "HPRT0_SUSP" and
> "PCGCTL_STOPPCLK" even with DWC2_POWER_DOWN_PARAM_NONE.  Do you
> disagree?
Yes dwc2_port_suspend() does but that is a different implementation
> 
> I completely agree that on mainline _dwc2_hcd_suspend() _does not_ set
> these bits with DWC2_POWER_DOWN_PARAM_NONE.  That is what my patch
> fixes.
Yes so I was pointing to that.
> 
> 
> -Doug
> 

I have performed testes and made sure that the patch is ok. It is just 
that I am not sure if it does really save power. I have not been able to 
see if any power is saved.

So I am ok with this patch.

-- 
Regards,
Artur

  parent reply index

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-18  0:13 [PATCH v2 0/5] USB: dwc2: Allow wakeup from suspend; enable for rk3288-veyron Douglas Anderson
2019-04-18  0:13 ` [v2,1/5] usb: dwc2: bus suspend/resume for hosts with DWC2_POWER_DOWN_PARAM_NONE Doug Anderson
2019-04-18  0:13   ` [PATCH v2 1/5] " Douglas Anderson
2019-04-29  8:43   ` [v2,1/5] " Artur Petrosyan
2019-04-29  8:43     ` [PATCH v2 1/5] " Artur Petrosyan
2019-04-29 17:33     ` [v2,1/5] " Doug Anderson
2019-04-29 17:33       ` [PATCH v2 1/5] " Doug Anderson
2019-04-30  6:05       ` [v2,1/5] " Artur Petrosyan
2019-04-30  6:05         ` [PATCH v2 1/5] " Artur Petrosyan
2019-05-01  1:51         ` [v2,1/5] " Doug Anderson
2019-05-01  1:51           ` [PATCH v2 1/5] " Doug Anderson
2019-05-03  8:20           ` [v2,1/5] " Artur Petrosyan
2019-05-03  8:20             ` [PATCH v2 1/5] " Artur Petrosyan
2019-05-03 15:03             ` [v2,1/5] " Doug Anderson
2019-05-03 15:03               ` [PATCH v2 1/5] " Doug Anderson
2019-05-07  7:26               ` Artur Petrosyan [this message]
2019-05-01 23:58   ` [v2,1/5] " Doug Anderson
2019-05-01 23:58     ` [PATCH v2 1/5] " Doug Anderson
2019-05-03  8:25     ` [v2,1/5] " Artur Petrosyan
2019-05-03  8:25       ` [PATCH v2 1/5] " Artur Petrosyan
2019-05-03 15:07       ` [v2,1/5] " Doug Anderson
2019-05-03 15:07         ` [PATCH v2 1/5] " Doug Anderson
2019-05-07  7:05         ` Artur Petrosyan
2019-04-18  0:13 ` [v2,2/5] USB: Export usb_wakeup_enabled_descendants() Doug Anderson
2019-04-18  0:13   ` [PATCH v2 2/5] " Douglas Anderson
2019-04-18  0:13 ` [v2,3/5] Documentation: dt-bindings: Add snps,need-phy-for-wake for dwc2 USB Doug Anderson
2019-04-18  0:13   ` [PATCH v2 3/5] " Douglas Anderson
2019-04-25 12:40   ` [v2,3/5] " Felipe Balbi
2019-04-25 12:40     ` [PATCH v2 3/5] " Felipe Balbi
2019-04-25 18:09     ` [v2,3/5] " Doug Anderson
2019-04-25 18:09       ` [PATCH v2 3/5] " Doug Anderson
2019-04-25 19:58       ` [v2,3/5] " Doug Anderson
2019-04-25 19:58         ` [PATCH v2 3/5] " Doug Anderson
2019-05-02 18:36     ` [v2,3/5] " Doug Anderson
2019-05-02 18:36       ` [PATCH v2 3/5] " Doug Anderson
2019-04-30  1:23   ` [v2,3/5] " Rob Herring
2019-04-30  1:23     ` [PATCH v2 3/5] " Rob Herring
2019-04-30  5:25     ` [v2,3/5] " Doug Anderson
2019-04-30  5:25       ` [PATCH v2 3/5] " Doug Anderson
2019-04-18  0:13 ` [v2,4/5] USB: dwc2: Don't turn off the usbphy in suspend if wakeup is enabled Doug Anderson
2019-04-18  0:13   ` [PATCH v2 4/5] " Douglas Anderson
2019-04-25 12:41   ` [v2,4/5] " Felipe Balbi
2019-04-25 12:41     ` [PATCH v2 4/5] " Felipe Balbi
2019-04-18  0:13 ` [v2,5/5] ARM: dts: rockchip: Allow wakeup from rk3288-veyron's dwc2 USB ports Doug Anderson
2019-04-18  0:13   ` [PATCH v2 5/5] " Douglas Anderson
2019-04-18 12:40 ` [PATCH v2 0/5] USB: dwc2: Allow wakeup from suspend; enable for rk3288-veyron Minas Harutyunyan
2019-04-18 15:54   ` Doug Anderson
2019-04-19 11:43     ` Artur Petrosyan
2019-04-19 16:44       ` Artur Petrosyan
2019-04-22 15:50         ` Artur Petrosyan

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