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From:   Neal Liu <neal_liu@aspeedtech.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC:     Felipe Balbi <balbi@kernel.org>,
        Alan Stern <stern@rowland.harvard.edu>,
        Roger Quadros <roger.quadros@nokia.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        BMC-SW <BMC-SW@aspeedtech.com>
Subject: RE: [PATCH v2] usb: gadget: f_mass_storage: Make CD-ROM emulation
 works with Windows OS
Thread-Topic: [PATCH v2] usb: gadget: f_mass_storage: Make CD-ROM emulation
 works with Windows OS
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Date:   Mon, 27 Jun 2022 02:31:02 +0000
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> On Fri, Jun 24, 2022 at 10:19:16AM +0800, Neal Liu wrote:
> > Add read TOC with format 1 to support CD-ROM emulation with
>=20
> What is "TOC"?  What is "format 1"?
>=20
> > Windows OS.
>=20
> Which versions of Windows support this?
>=20
> > This patch is tested on Windows OS Server 2019.
>=20
> Does this fix a regression where we used to support this?  Or is this a n=
ew
> feature of Windows?

We used to support this. I should add "Fixes" for the information.

>=20
>=20
> >
> > Signed-off-by: Neal Liu <neal_liu@aspeedtech.com>
> > ---
> >  drivers/usb/gadget/function/f_mass_storage.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/usb/gadget/function/f_mass_storage.c
> > b/drivers/usb/gadget/function/f_mass_storage.c
> > index 3a77bca0ebe1..9edf76c22605 100644
> > --- a/drivers/usb/gadget/function/f_mass_storage.c
> > +++ b/drivers/usb/gadget/function/f_mass_storage.c
> > @@ -1209,7 +1209,8 @@ static int do_read_toc(struct fsg_common
> > *common, struct fsg_buffhd *bh)
> >
> >  	switch (format) {
> >  	case 0:
> > -		/* Formatted TOC */
> > +	case 1:
> > +		/* Formatted TOC, Session info */
> >  		len =3D 4 + 2*8;		/* 4 byte header + 2 descriptors */
> >  		memset(buf, 0, len);
> >  		buf[1] =3D len - 2;	/* TOC Length excludes length field */
> > @@ -1250,7 +1251,7 @@ static int do_read_toc(struct fsg_common
> *common, struct fsg_buffhd *bh)
> >  		return len;
> >
> >  	default:
> > -		/* Multi-session, PMA, ATIP, CD-TEXT not supported/required */
> > +		/* PMA, ATIP, CD-TEXT not supported/required */
>=20
> So case 1 is "multi-session"?  Please document this properly.
>=20

Okay, I'll revise it properly.