linux-kernel - Re: [PATCH V12 1/1] usb:serial: Add Fintek F81532/534 driver

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Date:   Tue, 29 Nov 2016 10:33:16 +0800
From:   "Ji-Ze Hong (Peter Hong)" <hpeter@...il.com>
To:     Johan Hovold <johan@...nel.org>
Cc:     gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, tom_tsai@...tek.com.tw,
        peter_hong@...tek.com.tw,
        "Ji-Ze Hong (Peter Hong)" <hpeter+linux_kernel@...il.com>
Subject: Re: [PATCH V12 1/1] usb:serial: Add Fintek F81532/534 driver

Hi Johan,

Johan Hovold 於 2016/11/24 下午 11:04 寫道:
> On Mon, Nov 14, 2016 at 01:37:59PM +0800, Ji-Ze Hong (Peter Hong) wrote:
>> This driver is for Fintek F81532/F81534 USB to Serial Ports IC.

>> +	}
>> +
>> +	if (size_bulk_out != F81534_WRITE_BUFFER_SIZE ||
>> +			size_bulk_in != F81534_MAX_RECEIVE_BLOCK_SIZE) {
>> +		dev_err(dev, "%s: endpoints packet size not matched\n",
>> +				__func__);
>
> Similarly: "unsupported endpoint max packet size\n".
>
> But just to be clear: You do want to bail out if connected at full
> speed? You could also ask usb-serial core to allocate large enough
> buffers (e.g. by setting the bulk_out_size driver field) and the host
> controller will handle partitioning.

Yes, this product cannot run on USB full-speed currently due to the
bulk-out endpoint design. It need use 512 bytes packet size to transmit
4 ports TX data, but USB Full-speed only provide 64 byte. The F81534
will treat the all bulk-out data as port 0 although the host will spilt
512byte to 8 x 64bytes packets.

-- 
With Best Regards,
Peter Hong