Ticket #5135 (closed defect: duplicate)
Problem with Serial ports when transfer exceeds 256 bytes
Reported by: | raccoonone | Owned by: | |
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Component: | other | Version: | VirtualBox 3.0.8 |
Keywords: | serial | Cc: | |
Guest type: | Linux | Host type: | Windows |
Description
When passing through a connection to a serial device VirtualBox doesn't send the data correctly. If the device sends more than 256bytes of data at a time VirtualBox seems to buffer it into 256byte piece, and only sends a piece when there is a communication from the OS to the device. I'm running VirtualBox on a Windows XP host, with an Ubuntu Guest.
Change History
comment:2 in reply to: ↑ 1 Changed 13 years ago by raccoonone
Replying to frank:
How is the serial port connected to the host (VM settings)?
I have it configured as: Port Number: COM8 Port Mode: Host Device
Anything else you need to know?
comment:4 Changed 13 years ago by frank
Well, there is indeed buffering in the host part of the serial device implementation. The send buffer is 128 bytes long but as far as I can see, as soon as one byte arrives it is forwarded to the host's serial interface. But it can happen that the guest is sending too fast: If the buffer overruns, bytes will be dropped. Do you experience data loss or just bursts?
comment:5 Changed 13 years ago by raccoonone
Bursts. It will send all of the data from the device to the guest, if I keep "pinging" the device by sending some data from the guest to the device.
comment:6 Changed 13 years ago by raccoonone
This is still a problem in 3.0.12, do you need an additional information to debug this?
comment:7 Changed 13 years ago by replykate
I have the same problem. (sorry for my bad english I am french ). I tried to send a array (trame) from a windows xp host to a ubuntu (in VM). Only 258 bytes were send. If I try to send more, all my array is corrupted.
I tried to slow down transfert but no changement.
OS Host: WINDOWS XP SP3. OS Guest: Ubuntu 9.10. guest addon installed.
speed: 9600 bauds.
How is the serial port connected to the host (VM settings)?