﻿ticket	summary	version	created	modified	_changetime	_description	_reporter
4358	Break signal on serial port is not delivered to the port in vm	VirtualBox 2.2.4	2009-07-02T15:30:13Z	2011-07-25T14:25:03Z	2011-07-25T14:25:03Z	"On the host machine, I run an application that listens to COM port and reacts when the port sends Break signal. To the port I connect a device capable of sending Break signal, and the application reacts as programmed.

In Windows v.m. I specify COM port mapped to the real port on the host machine. Then I run the same application in the virtual machine and have the device send break signal. But the application in v.m. does not see it.

Break signal is described at 
http://support.microsoft.com/kb/119506

its implementation in Visual Basic at 
http://msdn.microsoft.com/en-us/library/aa259405(VS.60).aspx

I can provide the sample program demonstrating this, if needed.


"	vadimrapp
8947	Serial port raw mode should use O_APPEND for the file	VirtualBox 4.0.8	2011-05-23T02:51:16Z	2016-08-22T09:41:00Z	2016-08-22T09:41:00Z	"When setting a serial port to output to a file, the file should be opened with the O_APPEND flag. This allows the user to insert markers into the file (using ""echo marker >> file"" from the host machine) that will not be overwritten by virtualbox.

This change should literally be a one-liner.

Shachar"	Shachar Shemesh
12162	Serial Port output slows down VM	VirtualBox 4.2.18	2013-10-06T13:53:10Z	2019-09-18T22:57:01Z	2019-09-18T22:57:01Z	"I have a linux VM, with a kernel command-line saying console=ttyS0,115200 

With no serial port enabled, or a disconnected serial port, there are no problems. As soon as I redirect the serial port to a local file, the guest slows down significantly.

Booting the same guest using VMware Player (with the serial port also redirected to a file) does not show such a large performance penalty.

Alternatively, is there a faster solution to get /dev/console output onto a file on the host?"	AxelFontaine
17093	Serial I/O troubles between Guest and Host	VirtualBox 5.1.26	2017-09-18T08:53:46Z	2023-01-30T04:57:12Z	2023-01-30T04:57:12Z	"I've only personally seen this in a Windows 10 Pro (64-bit) host environment. But some others I've been in touch with seem to have this with other configurations too.

Scenario:

Host running Windows 10 Pro (64-bit) on computer with no physical COM ports (Lenovo T470p laptop). Guest can be ""anything"", but I've tested with FreeDOS, Ubuntu Linux 16/17, and Windows XP. Using NetSerial (http://pcmicro.com/netserial/) to emulate a COM port. NetSerial will behave as a COM port and as a ""modem emulator"" to allow ""ATDTfoo.bar"" to establish a Telnet session to foo.bar.

In VB Guest Config, I set up the serial port as needed. When Guest OS is launched, the results vary. But there seems to be flow control issues between the Guest and the Host. I've been talking to the author of NetSerial and have been testing with beta versions of NetSerial as well. He sets the correct flags for flow control, etc. But somwhere between the Guest and the Host, data is lost or delayed indefinitely.

When booting a Linux Guest in this setup, doing ""dmesg |grep tty"" does reveal that Linux has detected a 16550A UART on COM1, which is good thus far. Opening a Linux terminal emulator (any will do) using /dev/ttyS0, data IS being sent to NetSerial on the Windows Host. Using it's ""monitor"", I can see data being received from the Client terminal emulator. I can also see data being sent FROM NetSerial into the COM port. On the Guest, however, nothing is received.

When booting a FreeDOS Guest in this setup, I get similar results to the above. Data missing. Data delayed. Flow control issues, etc. 

Every application that I have tested with is requesting flow control to be CTS/RTS (hardware) and not XON/XOFF.

In almost exactly the same scenario, if I ""move"" NetSerial so that it runs inside the guest (Windows XP), there is no problem whatsoever. In that case, NetSerial is emulating a COM port and using Windows XP Guest Network to reach the Internet. No data being lost. No flow control issues.

So this is definitely related to the ""bridge"" between the COM port emulator running on the Host side of things.

There's still quite a bit of use left for serial device I/O, so I would expect this to work 100% in a product of VirtualBox's maturity. This problem has been present in at least the past 8-10 releases, and I suspect before that.

This is not a case of misconfiguration."	joho68
17239	Serial port missing characters.	VirtualBox 5.2.0	2017-11-04T14:38:09Z	2017-12-07T08:32:04Z	2017-12-07T08:32:04Z	"Using 'Windows 10' as host, and being Linux 'Ubuntu 14.04 LTS' as guest, with 
Virtual Box 5.2.0 and its associated guest additions, once the guest Ubuntu has
been launched, by using the serial port: /dev/ttyS0, from within the guest, some 
characters are missed (they don't appear in the serialized stream of data 
shown in the terminal's screen).

This problem is also present in other versions of virtual box (for example: 
5.1.18). On the other hand, this issue works fine under Windows 7 as host 
using virtual box 5.1.18.

¿Perhaps is there some incompatibility between guest additions and windows 10?
"	jim_
17350	use of serial port crashes VM w/ non-mainstream OS	VirtualBox 5.1.30	2017-12-06T11:43:22Z	2018-01-10T22:44:44Z	2018-01-10T22:44:44Z	"I try to run a Cisco router VM based on x86 known as IOSv (virtual IOS). The same image works perfectly fine with KVM and VMware Fusion / Workstation / ESXi. It also works OK in VB as long as there is no serial port connected. However, the serial console is the only way to access the box (assuming it does not have a configuration which also would allow to SSH / Telnet into the VM / router).

When starting up the VM in VB it displays the Grub boot loader and then, in 9 out of 10 cases, instantly displays a Guru meditation instead of loading the kernel image. This is regardless of using a Pipe, a TCP port or a raw file for the port. Haven't tried host device as that's useless for our use case. If the port is enabled but  'disconnected' then the VM comes up fine all the time.

This was tested on a Mac (MacBook Pro Mid2017, Intel Core i7) with 
- VB 5.1.30
- VB 5.0.40
- VB 5.2.2

I also ran into this problem on Linux. Here I run VB in a nested VM running on KVM on an Intel i7 w/ host-passthrough and 5.0.40 on Ubuntu Xenial... It seems to work more often there (more than 1 in 10) but also produces the Guru meditation when trying often enough.
"	Ralph Schmieder
17480	Linux boot slows to a crawl when serial port is enabled for serial getty (console).	VirtualBox 5.2.6	2018-01-19T04:03:55Z	2021-12-16T21:19:26Z	2021-12-16T21:19:26Z	"This issue first appeared in VirtualBox 5.2.6. This issue does *NOT* exist in VirtualBox 5.1.32 or earlier.

We are using a custom 64 bit Linux OS that uses a serial getty on ttyS0. Prior to VirtualBox 5.2.6, the boot took less than ten seconds. The boot now takes about 20 minutes under VirtualBox 5.2.6.

The UART settings in question are as follows:

{{{ 
UART 1: I/O base: 0x03f8, IRQ: 4, attached to pipe (server) '/tmp/ttyS0'
UART 2: I/O base: 0x02f8, IRQ: 3, attached to pipe (server) '/tmp/ttyS1' 
}}}

The boot returns to normal when using VirtualBox 5.2.6 if UART 1 is turned off. Or, we can leave both UARTs on and revert back to VirtualBox 5.1.32.

I have attached log files from VirtualBox 5.2.6. One log file is with UART 1 turned on (slow boot), and the other is with UART 1 turned off (fast boot)."	chuckwolber
18668	Problem with sharing serial port after upgrade from 5.2.28 to 6.0.X	VirtualBox 6.0.8	2019-05-22T12:00:47Z	2021-12-05T20:33:25Z	2021-12-05T20:33:25Z	"When I try to use a shared COM port (host device) on a guest running DOS 6.22 (using a legacy software for PLCs), on VirtualBox 6.0.8 (and also 6.0.6) I get errors like:
Serial#0: Failed to change parameters to 2400,NONE,5,1 -> VERR_INVALID_PARAMETER
and the software cannot communicate.

Everything works fine if I use VirtualBox 5.2.28 instead, with the same virtual machine.

The full log is attached."	stagadet
18789	serial port problems with VB 6.0.10	VirtualBox 6.0.10	2019-07-24T21:34:54Z	2020-01-20T08:52:20Z	2020-01-20T08:52:20Z	I had to set COM1 to raw file to get the windows guests to completely boot. It's like the boot up is in a boot loop if I set COM1 for Host device. Also, I have the second comport set to user defined but it works OK when set for Host device but there are occasional crashes where the guest can't see the comport. I don't have this problem with VB 5.2.x. see attached files	eelstrebor
18901	Using serial host device make guest boot hang	VirtualBox 6.0.10	2019-09-03T14:26:38Z	2020-01-30T16:05:48Z	2020-01-30T16:05:48Z	"I'm using the serial host device since a long time.
Using Fedora (from 20 now 30) host and XP host (because of sortware only running on Windows XP using serial device)
Until VB 5.12, everything worked thing.
But now, after update to Fedora 30, I had to update to the last VirtuaBox release (6.0.10).
My guest does not boot anymore (it hangs)
If i uncheck serial port, it boots.
If I keep serial port and disable it, My guest Boots, serial COM is visible but unsuable (which is normal).

VBox.log is showing this : (see file attached)
 Failed to change parameters to 9600,EVEN,7,1 -> VERR_DEV_IO_ERROR
 Failed to change parameters to 1200,EVEN,7,1 -> VERR_DEV_IO_ERROR

"	cderenne
20132	Guest Windows XP x86 Does Not Shutdown with Serial Ports Enabled	VirtualBox 6.1.16	2021-01-17T21:44:24Z	2021-10-02T09:33:32Z	2021-10-02T09:33:32Z	"Host is Windows 10 x64. Serial ports COM 1-4 are from PCI-E Moxa CP-144EL Series card running the version 3.00 driver. All COM ports are working properly on host OS.

Guest OS Windows XP x86 recognizes COM ports 1-4 through the Host Device port mode. Port path on !VirtualBox is set to the identical port on host PC. Communication with a connected device is successful.

Upon shutdown of guest OS the shutdown process hangs with:

{{{
00:05:15.665094 HostSerial#0: The underlying host device run into a fatal error condition VINF_SUCCESS, any data transfer is disabled
00:05:15.665170 HostSerial#1: The underlying host device run into a fatal error condition VINF_SUCCESS, any data transfer is disabled
00:05:15.665256 HostSerial#2: The underlying host device run into a fatal error condition VINF_SUCCESS, any data transfer is disabled
00:05:15.665307 HostSerial#3: The underlying host device run into a fatal error condition VINF_SUCCESS, any data transfer is disabled
}}}

Host has to be rebooted afterwards or rarely BSOD error happens upon shutdown."	yordan
20782	VirtualBox revert to invalid options automatically	VirtualBox 6.1.28	2022-01-20T14:46:50Z	2022-01-20T14:46:50Z	2022-01-20T14:46:50Z	"Hello,
  I have installed a custom Linux guest OS and I wish to keep my video card to VBoxVGA. Unfortunately VirtualBox every time I change the selection or visit the settings page, by default revert this setting to VMsvga without prompt and this driver causes kernel panic to my VM. This is not happening in older versions of VirtualBox."	ssavva
