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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 Stübner" <heiko@sntech.de>,
	"Alan Stern" <stern@rowland.harvard.edu>,
	"Alexandru M Stan" <amstan@chromium.org>,
	"open list:ARM/Rockchip SoC..."
	<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>, Chris <zyw@rock-chips.com>,
	"Matthias Kaehlcke" <mka@chromium.org>,
	"Ryan Case" <ryandcase@chromium.org>,
	"Amelie Delaunay" <amelie.delaunay@st.com>,
	"Julius Werner" <jwerner@chromium.org>,
	"Elaine Zhang" <zhangqing@rock-chips.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	LKML <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 07:05:45 +0000
Message-ID: <SN1PR12MB243183AAC5636C23144634FBA7310@SN1PR12MB2431.namprd12.prod.outlook.com> (raw)
In-Reply-To: <CAD=FV=V97+_cQ1aD=w_a3SifGOG3M5DPvcnvxYVUJMkX_WLTFg@mail.gmail.com>

Hi,

On 5/3/2019 19:08, Doug Anderson wrote:
> Hi,
> 
> On Fri, May 3, 2019 at 1:25 AM Artur Petrosyan
> <Arthur.Petrosyan@synopsys.com> wrote:
>>
>> On 5/2/2019 03:58, Doug Anderson wrote:
>>> Hi,
>>>
>>>
>>> On Wed, Apr 17, 2019 at 5:15 PM Douglas Anderson <dianders@chromium.org> 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=DwIBaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=9hPBFKCJ_nBjJhGVrrlYOeOQjP_HlVzYqrC_D7niMJI&m=7rxT8EFX9mqUDtTL4P7iuzYNsYROe9rxHGCresSKPTg&s=lTaNUA2XIYPat417fkd1A4Zpvb5eyYtTc1H_NIfW8Vw&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.
>>>> * If we don't do something like this commit we don't get into as low
>>>>     of a power mode.
>>>
>>> OK, I spent the day digging more into this patch to confirm that it's
>>> really the right thing to do.  ...and it still seems to be.
>>>
>>> First off: I'm pretty sure the above sentence "If we don't do
>>> something like this commit we don't get into as low of a power mode."
>>> is totally wrong.  Luckily it's "after the cut" and not part of the
>>> commit message.  Specifically I did a bunch of power testing and I
>>> couldn't find any instance saving power after this patch.
>>>
>>> ...but, then I looked more carefully at all the history of this
>>> commit.  I ended up at:
>>>
>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__chromium-2Dreview.googlesource.com_c_chromiumos_third-5Fparty_kernel_-2B_306265_&d=DwIBaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=9hPBFKCJ_nBjJhGVrrlYOeOQjP_HlVzYqrC_D7niMJI&m=7rxT8EFX9mqUDtTL4P7iuzYNsYROe9rxHGCresSKPTg&s=LiyyIyaCPmr88nJeI7TCGtoJBFLRWir_reikYtAHHDw&e=
>> Looking at this code review I see that this patch fixes whatever issues
>> you have on Chrome OS 3.14. But your patch has landed on the top of
>> latest Kernel version. With the latest version I think you would not
>> have the regression issue.
>> So you are fixing Chrome OS 3.14.
> 
> I'm confused why you ignored the rest of my email where I said I also
> ported it to 4.19 (which, from a dwc2 host point of view, is pretty
> much mainline) and saw that the patch was still needed.
I didn't ignore it just I had to perform testes and reply to it with 
another email.
> 
> -Doug
> 
I spent yesterday debugging and performing testes with Linux Mainline. 
So when we don't have any of power saving modes supported and the 
power_down is DWC2_POWER_DOWN_PARAM_NONE. We can set "PCGCTL_STOPPCLK" 
bit whenever there is suspend ( Checked the programming guide and data 
book). I have not seen any case that this affects the flow. I have not 
been able to see if after setting "PCGCTL_STOPPCLK" bit there is any 
power saved or driver behaved differently. Maybe it is platform depended 
. However, there is a possibility that this might save power.

So as this is not breaking anything. 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
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 [this message]
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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