From: Alan Stern <stern@rowland.harvard.edu>
To: Felipe Balbi <balbi@kernel.org>
Cc: Jacky.Cao@sony.com, <gregkh@linuxfoundation.org>,
<linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<Kento.A.Kobayashi@sony.com>
Subject: Re: [PATCH] USB: dummy-hcd: fix power budget for SuperSpeed mode
Date: Wed, 4 Sep 2019 10:21:40 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1909041017180.1722-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <87sgpcmr7v.fsf@gmail.com>
On Wed, 4 Sep 2019, Felipe Balbi wrote:
>
> Hi,
>
> <Jacky.Cao@sony.com> writes:
>
> > The power budget for SuperSpeed mode should be 900 mA
> > according to USB3.0 specification, so set the power
> > budget to 900 mA for dummy_start_ss which is only used
> > for SuperSpeed mode.
> >
> > If the max power consumption of SuperSpeed device is
> > larger than 500 mA, insufficient available bus power
> > error happens in usb_choose_configuration function
> > when the device connects to dummy hcd.
> >
> > Signed-off-by: Jacky Cao <Jacky.Cao@sony.com>
> > ---
> > drivers/usb/gadget/udc/dummy_hcd.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
> > index 8414fac..52f2cf5 100644
> > --- a/drivers/usb/gadget/udc/dummy_hcd.c
> > +++ b/drivers/usb/gadget/udc/dummy_hcd.c
> > @@ -48,6 +48,7 @@
> > #define DRIVER_VERSION "02 May 2005"
> >
> > #define POWER_BUDGET 500 /* in mA; use 8 for low-power port testing */
> > +#define POWER_BUDGET_3_0 900 /* in mA */
> >
> > static const char driver_name[] = "dummy_hcd";
> > static const char driver_desc[] = "USB Host+Gadget Emulator";
> > @@ -2432,7 +2433,7 @@ static int dummy_start_ss(struct dummy_hcd *dum_hcd)
> > dum_hcd->rh_state = DUMMY_RH_RUNNING;
> > dum_hcd->stream_en_ep = 0;
> > INIT_LIST_HEAD(&dum_hcd->urbp_list);
> > - dummy_hcd_to_hcd(dum_hcd)->power_budget = POWER_BUDGET;
> > + dummy_hcd_to_hcd(dum_hcd)->power_budget = POWER_BUDGET_3_0;
> > dummy_hcd_to_hcd(dum_hcd)->state = HC_STATE_RUNNING;
> > dummy_hcd_to_hcd(dum_hcd)->uses_new_polling = 1;
> > #ifdef CONFIG_USB_OTG
>
> Alan, I suppose you're okay with this change?
Yes. Except that I think the name POWER_BUDGET_3_0 is a little odd.
It implies that this change is specific to USB 3.0 -- but it isn't.
USB 3.1 and 3.2 also have a 900 mA limit, right?
So please consider changing the name to POWER_BUDGET_3.
Alan Stern
next prev parent reply other threads:[~2019-09-04 14:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-04 7:52 [PATCH] USB: dummy-hcd: fix power budget for SuperSpeed mode Jacky.Cao
2019-09-04 7:54 ` Felipe Balbi
2019-09-04 7:58 ` Greg KH
2019-09-04 8:52 ` Jacky.Cao
2019-09-04 10:01 ` Greg KH
2019-09-04 14:21 ` Alan Stern [this message]
2019-09-05 4:18 ` Jacky.Cao
[not found] <16EA1F625E922C43B00B9D82250220500871C7D7@APYOKXMS108.ap.sony.com>
2019-09-04 7:46 ` Felipe Balbi
2019-09-04 7:54 ` Jacky.Cao
[not found] <16EA1F625E922C43B00B9D8225022050086ECF6A@APYOKXMS108.ap.sony.com>
[not found] ` <16EA1F625E922C43B00B9D8225022050086F86B4@APYOKXMS108.ap.sony.com>
2019-09-04 6:12 ` Kobayashi, Kento (Sony)
2019-09-04 6:19 ` Felipe Balbi
2019-09-04 6:57 ` Kobayashi, Kento (Sony)
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