[v5] cdc-acm: fix abnormal DATA RX issue for Mediatek Preloader.

[macpaul.lin@mediatek.com]

On Tue, 2018-12-18 at 22:26 +0800, Macpaul Lin wrote:
> On Tue, 2018-12-18 at 14:37 +0100, Oliver Neukum wrote:
> > On Di, 2018-12-18 at 13:38 +0100, Johan Hovold wrote:
> > > On 
> > > > @@ -1655,7 +1662,10 @@ static int acm_pre_reset(struct usb_interface *intf)
> > > >  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
> > > >  	},
> > > >  	{ USB_DEVICE(0x0e8d, 0x0003), /* FIREFLY, MediaTek Inc; andrey.arapov@gmail.com */
> > > > -	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
> > > > +	.driver_info = DISABLE_ECHO, /* DISABLE ECHO in termios flag */
> > > 
> > > I just noticed that you remove the NO_UNION_NORMAL here, which looks
> > > wrong and definitely requires a motivation.
> > > 
> > > Thanks,
> > > Johan
> > > 
> > 
> > Hi,
> > 
> > thank you and thank you Johan.
> > Unfortunately I cannot take this until the issue with the removed
> > quirk is clarified.
> > 
> > 	Regards
> > 		Oliver
> > 
> 
> Hi,
> Thanks Johan's help on reviewing the updated patches.
> According to Andrey's patch, the commit said this change is for
> "Samsung X180 China cellphone" which might be also a Mediatek SoC based
> phone using Mediatek VID.
> https://goo.gl/a9ddNq (I've add a url for reference here).
> 
> But I'm not sure the PID is for Mediatek's BROM or customized Preloader.
> (Both should be able to apply DISABLE_ECHO flag).
> Maybe I can simply update PATCH v6 by removing FIREFLY if any one has
> problem here.
> Let's also loop Andrey for clarification.

Hi all,

After double check the PID/VID officially used (registered) by Mediatek
Inc. The following VID/PID maps to the corresponding USB interface of
the firmware of cell phone.
VID:0x0e8d, PID:0x0003: Mediatek BROM. 
VID:0x0e8d, PID:0x2000: Mediatek Preloader.

I will update Patch v6 for changing Andrey's previous comments.

Thanks.

Regards,
Macpaul Lin.