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Message-ID: <DM8PR02MB8198F2BFE9E933CC8F2C148BE3029@DM8PR02MB8198.namprd02.prod.outlook.com>
Date: Tue, 1 Mar 2022 02:30:00 +0000
From: "Linyu Yuan (QUIC)" <quic_linyyuan@...cinc.com>
To: "mka@...omium.org" <mka@...omium.org>,
"Linyu Yuan (QUIC)" <quic_linyyuan@...cinc.com>
CC: "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"Tao Wang (Consultant) (QUIC)" <quic_wat@...cinc.com>,
"balbi@...nel.org" <balbi@...nel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"dianders@...omium.org" <dianders@...omium.org>,
"frowand.list@...il.com" <frowand.list@...il.com>,
"hadess@...ess.net" <hadess@...ess.net>,
"krzk@...nel.org" <krzk@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"mathias.nyman@...el.com" <mathias.nyman@...el.com>,
"michal.simek@...inx.com" <michal.simek@...inx.com>,
"peter.chen@...nel.org" <peter.chen@...nel.org>,
"ravisadineni@...omium.org" <ravisadineni@...omium.org>,
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Subject: RE: 回复: 回复: Re: [PATCH v20 3/5] usb: misc: Add onboard_usb_hub driver
> From: mka@...omium.org <mka@...omium.org>
> Sent: Tuesday, March 1, 2022 2:29 AM
> To: Linyu Yuan (QUIC) <quic_linyyuan@...cinc.com>
> Cc: gregkh@...uxfoundation.org; Tao Wang (Consultant) (QUIC)
> <quic_wat@...cinc.com>; balbi@...nel.org; devicetree@...r.kernel.org;
> dianders@...omium.org; frowand.list@...il.com; hadess@...ess.net;
> krzk@...nel.org; linux-kernel@...r.kernel.org; linux-usb@...r.kernel.org;
> mathias.nyman@...el.com; michal.simek@...inx.com;
> peter.chen@...nel.org; ravisadineni@...omium.org; robh+dt@...nel.org;
> rogerq@...nel.org; stern@...land.harvard.edu; swboyd@...omium.org
> Subject: Re: 回复: 回复: Re: [PATCH v20 3/5] usb: misc: Add
> onboard_usb_hub driver
>
> >
> > Hi Greg and mka,
> >
> > Let's make it clear that we are talking about once this driver is approved
> into usb tree,
> > If we use different USB HUB which have VID/PID not defined in this driver,
> > We need to update this driver.
> >
> > But if we defined VID/PID in device tree(for a specific board, manufacture
> should know VID/PID from HUB it used),
> > dynamic parsed by the driver, then we don't need to change this driver
> (increase VID/PID table).
>
> As per my earlier reply, the kernel/USB core uses the VID:PID reported
> by the USB device, the compatible string in the device tree is purely
> informational. That's not something that could be changed by this
> driver.
I can't fully understand this comment, could you please share step if we want to add a new HUB support, what should we do ? nothing ?
If do nothing, can we remove id_table from onboard_hub_usbdev_driver ?
>
> And even if the VID:PID from the device tree was used: how is the
> kernel supposed to know that the onboard_hub driver should be
> probed for a given VID:PID from the device tree, without listing
> the VID:PID (or compatible string) in the driver (which is what
> you seem to seek to avoid)?
In my opinion, if it need update VID/PID table in this driver to support a new HUB,
we can parse VID/PID from device tree and create dynamic VID/PID entry to id_table of onboard_hub_usbdev_driver.
Hope you can understand what I said.
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