Rockbox

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  • Task Type Patches
  • Category Drivers
  • Assigned To No-one
  • Operating System Another
  • Severity Low
  • Priority Very Low
  • Reported Version Daily build (which?)
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Attached to Project: Rockbox
Opened by mbu - 2009-02-16

FS#9917 - Cowon D2 Usb Serial

Here’s a patch to have a functional usb_serial driver allowing the use of “Logf over Usb” debug function.

I must admit I'm a little confused by this patch. I've committed the parts that are necessary to get USB support compiling again (USB_NUM_ENDPOINTS, usb_attach() etc), and it seems that logf-over-usb works for me using just those changes.

Occasionally there are some repeated and/or missing characters at the end of logf lines - presumably the rest of your changes are aimed at fixing that? Unfortunately when I apply the full patch my D2 freezes when I connect the USB cable.

Could you maybe explain what your changes are doing? I'm quite unfamiliar with the existing USB driver so need all the help I can get…

mbu commented on 2009-03-10 12:04

Yes you're right, the rest of the patch aim to fix those missing parts. It has something to do with alignment in memory.
I get some code from ifp_usb_serial.c, from the usb_get_packet and usb_send functions to have word-aligned data in memory before sending/reading register.

Another part of the patch in usb_drv_send_nonblocking :
- ep→count = count;
+ ep→count = 0;
is a bug fix I think because ep→count contains the number of send bytes and this value is changed in usb_drv_write_ep. I assumed it must be set to 0 before first call to usb_drv_write_ep.
Without this fix I got a Panic because the number of bytes send is incorrectly reported to usb_serial_transfer_complete.
It seems that recents changes in usb_serial.c made it works without this patch because the number of send bytes is not used anymore in usb_serial_transfer_complete.

I will update my working copy tonight and try to reproduce the freeze.

mbu commented on 2009-03-11 22:21

I made some test on rev 20283. I first had the freeze you described with a fresh update and no patch.
After some tests it finally worked without any changes. I experience very strange behaviors with usb.
There's some factors I don't understand.

I made an update of the patch with rev 20283.

this doesn't allows to connect D2 to PC without rebooting to original FW, isn't it?

mbu commented on 2010-10-26 07:27

This patch allowed the D2 to be seen as an usb serial device, allowing to use logfoverusb.
This does not make usb mass storage work, and this is quite old.

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