In message: <51fb5230.3000...@bitfrost.no>
Hans Petter Selasky <h...@bitfrost.no> writes:
> On 08/01/13 16:07, SAITOU Toshihide wrote:
>> My UVC cam is not working with the musb_otg driver and
>> libusb(3) on the BeagleBone Black.
>>
>
> Hi,
>
> It might be that the packet multiplier is not set
> correctly. Try to figure out which register this is, and
> simply set the bits correctly.
>
> Thank you!
>
> --HPS
>
>> With the following changes to the musb_otg.c, it feels like
>> the transaction is performed as expected but the data
>> doesn't pass to the libusb_transfer's buffer. Does anyone
>> know what is wrong?
Thank you for your information, but still I don't understand
what is the packet multiplier. Fortunately, there is a
progress.
With the patch at the end, the data from the UVC camera is
arrived into the libusb_transfer's buffer. Now the problem is
that the data of each transaction is scattered into the buffer
of the packet.
(now)
| packet size | packet size | packet size | packet size |
| DATA0 | DATA1 | DATA2 | DATA0 |...
(expected)
| packet size | packet size | packet size |
| DATA0,1,2 | DATA0,1,2 | DATA0,1,2 |...
I think if the length of the packet is set using
libusb_set_iso_packet_length, all transaction data for the
packet should be packed into it, at this time, max packet size
is declared in the device descriptor so the device doesn't
send the packet larger than that. Are these right? If so, is
the musbotg_host_data_rx of musb_otg.c need to modify?
1729c1729
< MUSB2_WRITE_1(sc, MUSB2_REG_RXNAKLIMIT, 0);
---
> MUSB2_WRITE_1(sc, MUSB2_REG_RXNAKLIMIT, MAX_NAK_TO);
3162c3162
< frx = 12; /* 4K */
---
> frx = 10; /* 1K */
3164c3164
< MUSB2_VAL_FIFOSZ_4096 |
---
> MUSB2_VAL_FIFOSZ_512 |
4046c4046
< parm->hc_max_frame_size = 0xc00;
---
> parm->hc_max_frame_size = 0x400;
SAITOU Toshihide
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