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Subject: Re: [PATCH 5/5] USB: serial: f81232: fix bulk_in/out size
To:     Johan Hovold <johan@kernel.org>
Cc:     gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, peter_hong@fintek.com.tw,
        "Ji-Ze Hong (Peter Hong)" <hpeter+linux_kernel@gmail.com>
References: <1516607927-8887-1-git-send-email-hpeter+linux_kernel@gmail.com>
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 <20180130041150.GC3434@localhost>
From:   "Ji-Ze Hong (Peter Hong)" <hpeter@gmail.com>
Message-ID: <840d55b0-9ce2-846d-9bf5-8d0e67b8739e@gmail.com>
Date:   Thu, 1 Feb 2018 13:50:55 +0800
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Hi Johan,

Johan Hovold 於 2018/1/30 下午 12:11 寫道:
> On Mon, Jan 22, 2018 at 03:58:47PM +0800, Ji-Ze Hong (Peter Hong) wrote:
>> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
>> index a054f69446fd..f3ee537d643c 100644
>> --- a/drivers/usb/serial/f81232.c
>> +++ b/drivers/usb/serial/f81232.c
>> @@ -769,8 +769,7 @@ static struct usb_serial_driver f81232_device = {
>>   	},
>>   	.id_table =		id_table,
>>   	.num_ports =		1,
>> -	.bulk_in_size =		256,
>> -	.bulk_out_size =	256,
>> +	.bulk_out_size =	16,
> 
> So it seems you should really be setting bulk_in_size to 64 here (and
> possibly leave bulk_out_size unset) as that would appear to match your
> device buffer sizes.

Yes, we want to set the bulk_in_size as 64. The public datasheet has
some error with bulk in/out, the correct size is 64.

We had test the bulk_out_size set the same with internal TX FIFO will
make the best performance in tests, but it's ok to set 64. In my opinion
, I'll prefer to set 16.

The following information is the F81232 dump by lsusb:

Bus 002 Device 007: ID 1934:0706 Feature Integration Technology Inc. 
(Fintek)
Device Descriptor:
   bLength                18
   bDescriptorType         1
   bcdUSB               1.10
   bDeviceClass            0 (Defined at Interface level)
   bDeviceSubClass         0
   bDeviceProtocol         0
   bMaxPacketSize0        16
   idVendor           0x1934 Feature Integration Technology Inc. (Fintek)
   idProduct          0x0706
   bcdDevice            0.01
   iManufacturer           1 FINTEK
   iProduct                2 USB TO UART BRIDGE
   iSerial                 3 88635600168801
   bNumConfigurations      1
   Configuration Descriptor:
     bLength                 9
     bDescriptorType         2
     wTotalLength           39
     bNumInterfaces          1
     bConfigurationValue     1
     iConfiguration          0
     bmAttributes         0xa0
       (Bus Powered)
       Remote Wakeup
     MaxPower              100mA
     Interface Descriptor:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        0
       bAlternateSetting       0
       bNumEndpoints           3
       bInterfaceClass         0 (Defined at Interface level)
       bInterfaceSubClass      0
       bInterfaceProtocol      0
       iInterface              0
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            3
           Transfer Type            Interrupt
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0010  1x 16 bytes
         bInterval              10
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x82  EP 2 IN
         bmAttributes            2
           Transfer Type            Bulk
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0040  1x 64 bytes
         bInterval               0
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x01  EP 1 OUT
         bmAttributes            2
           Transfer Type            Bulk
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0040  1x 64 bytes
         bInterval               0
Device Status:     0x0000
   (Bus Powered)

Thanks
-- 
With Best Regards,
Peter Hong