Grub and usb serial support
Clash Royale CLAN TAG#URR8PPP
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How to access the grub menu using a usb serial converter?
I know it's possible to have grub menu in serial console, putting these lines in grub.conf:
serial --unit=0 --speed=9600 --word=8 --parity=no --stop=1
terminal serial
But with usb serial converter? In linux it is /dev/ttyUSB0 and I can use it to see boot messages.
linux usb grub
asked Jun 18 '13 at 13:42
Alessandro Pezzato
1458
add a comment |Â
up vote
4
down vote
favorite
How to access the grub menu using a usb serial converter?
I know it's possible to have grub menu in serial console, putting these lines in grub.conf:
serial --unit=0 --speed=9600 --word=8 --parity=no --stop=1
terminal serial
But with usb serial converter? In linux it is /dev/ttyUSB0 and I can use it to see boot messages.
linux usb grub
asked Jun 18 '13 at 13:42
Alessandro Pezzato
1458
1
might be of interest savannah.gnu.org/bugs/?36740
– frostschutz
Jun 19 '13 at 18:47
add a comment |Â
up vote
4
down vote
favorite
up vote
4
down vote
favorite
How to access the grub menu using a usb serial converter?
I know it's possible to have grub menu in serial console, putting these lines in grub.conf:
serial --unit=0 --speed=9600 --word=8 --parity=no --stop=1
terminal serial
But with usb serial converter? In linux it is /dev/ttyUSB0 and I can use it to see boot messages.
linux usb grub
asked Jun 18 '13 at 13:42
Alessandro Pezzato
1458
How to access the grub menu using a usb serial converter?
I know it's possible to have grub menu in serial console, putting these lines in grub.conf:
serial --unit=0 --speed=9600 --word=8 --parity=no --stop=1
terminal serial
But with usb serial converter? In linux it is /dev/ttyUSB0 and I can use it to see boot messages.
linux usb grub
linux usb grub
asked Jun 18 '13 at 13:42
Alessandro Pezzato
1458
asked Jun 18 '13 at 13:42
Alessandro Pezzato
1458
asked Jun 18 '13 at 13:42
Alessandro Pezzato
1458
asked Jun 18 '13 at 13:42
Alessandro Pezzato
1458
asked Jun 18 '13 at 13:42
Alessandro Pezzato
1458
1458
1
might be of interest savannah.gnu.org/bugs/?36740
– frostschutz
Jun 19 '13 at 18:47
add a comment |Â
1
might be of interest savannah.gnu.org/bugs/?36740
– frostschutz
Jun 19 '13 at 18:47
1
1
might be of interest savannah.gnu.org/bugs/?36740
– frostschutz
Jun 19 '13 at 18:47
might be of interest savannah.gnu.org/bugs/?36740
– frostschutz
Jun 19 '13 at 18:47
add a comment |Â
1 Answer
1
active
oldest
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0
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I guess serial output works only if there is something at the default address of the serial port. The kernel does not know what USB is in the moment when its output begins. A USB to serial converter does this: It looks like a serial port to the other device but like USB to the system itself. You need it the other way round: It must look like a serial port to the local system, not matter what it looks like to the other device.
answered Jun 18 '13 at 14:02
Hauke Laging
53.8k1282130
You're right. This is obvious. Linux kernel can use it as a serial device through /dev/ttyUSB0. But grub?
– Alessandro Pezzato
Jun 18 '13 at 15:04
1
@AlessandroPezzato Even the kernel cannot simply access it as a serial port. It needs to talk to the USB controller. Thus no output is possible until both USB and the adapter driver are available (usually as a module).
– Hauke Laging
Jun 18 '13 at 15:10
1
Right, kernel uses a module, usally ftdi or prolific. I guess something similar exists for grub.
– Alessandro Pezzato
Jun 18 '13 at 15:18
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
I guess serial output works only if there is something at the default address of the serial port. The kernel does not know what USB is in the moment when its output begins. A USB to serial converter does this: It looks like a serial port to the other device but like USB to the system itself. You need it the other way round: It must look like a serial port to the local system, not matter what it looks like to the other device.
answered Jun 18 '13 at 14:02
Hauke Laging
53.8k1282130
You're right. This is obvious. Linux kernel can use it as a serial device through /dev/ttyUSB0. But grub?
– Alessandro Pezzato
Jun 18 '13 at 15:04
1
@AlessandroPezzato Even the kernel cannot simply access it as a serial port. It needs to talk to the USB controller. Thus no output is possible until both USB and the adapter driver are available (usually as a module).
– Hauke Laging
Jun 18 '13 at 15:10
1
Right, kernel uses a module, usally ftdi or prolific. I guess something similar exists for grub.
– Alessandro Pezzato
Jun 18 '13 at 15:18
add a comment |Â
up vote
0
down vote
I guess serial output works only if there is something at the default address of the serial port. The kernel does not know what USB is in the moment when its output begins. A USB to serial converter does this: It looks like a serial port to the other device but like USB to the system itself. You need it the other way round: It must look like a serial port to the local system, not matter what it looks like to the other device.
answered Jun 18 '13 at 14:02
Hauke Laging
53.8k1282130
You're right. This is obvious. Linux kernel can use it as a serial device through /dev/ttyUSB0. But grub?
– Alessandro Pezzato
Jun 18 '13 at 15:04
1
@AlessandroPezzato Even the kernel cannot simply access it as a serial port. It needs to talk to the USB controller. Thus no output is possible until both USB and the adapter driver are available (usually as a module).
– Hauke Laging
Jun 18 '13 at 15:10
1
Right, kernel uses a module, usally ftdi or prolific. I guess something similar exists for grub.
– Alessandro Pezzato
Jun 18 '13 at 15:18
add a comment |Â
up vote
0
down vote
up vote
0
down vote
I guess serial output works only if there is something at the default address of the serial port. The kernel does not know what USB is in the moment when its output begins. A USB to serial converter does this: It looks like a serial port to the other device but like USB to the system itself. You need it the other way round: It must look like a serial port to the local system, not matter what it looks like to the other device.
answered Jun 18 '13 at 14:02
Hauke Laging
53.8k1282130
I guess serial output works only if there is something at the default address of the serial port. The kernel does not know what USB is in the moment when its output begins. A USB to serial converter does this: It looks like a serial port to the other device but like USB to the system itself. You need it the other way round: It must look like a serial port to the local system, not matter what it looks like to the other device.
answered Jun 18 '13 at 14:02
Hauke Laging
53.8k1282130
edited Jun 18 '13 at 15:06
answered Jun 18 '13 at 14:02
Hauke Laging
53.8k1282130
answered Jun 18 '13 at 14:02
Hauke Laging
53.8k1282130
answered Jun 18 '13 at 14:02
Hauke Laging
53.8k1282130
53.8k1282130
You're right. This is obvious. Linux kernel can use it as a serial device through /dev/ttyUSB0. But grub?
– Alessandro Pezzato
Jun 18 '13 at 15:04
1
@AlessandroPezzato Even the kernel cannot simply access it as a serial port. It needs to talk to the USB controller. Thus no output is possible until both USB and the adapter driver are available (usually as a module).
– Hauke Laging
Jun 18 '13 at 15:10
1
Right, kernel uses a module, usally ftdi or prolific. I guess something similar exists for grub.
– Alessandro Pezzato
Jun 18 '13 at 15:18
add a comment |Â
You're right. This is obvious. Linux kernel can use it as a serial device through /dev/ttyUSB0. But grub?
– Alessandro Pezzato
Jun 18 '13 at 15:04
1
@AlessandroPezzato Even the kernel cannot simply access it as a serial port. It needs to talk to the USB controller. Thus no output is possible until both USB and the adapter driver are available (usually as a module).
– Hauke Laging
Jun 18 '13 at 15:10
1
Right, kernel uses a module, usally ftdi or prolific. I guess something similar exists for grub.
– Alessandro Pezzato
Jun 18 '13 at 15:18
You're right. This is obvious. Linux kernel can use it as a serial device through /dev/ttyUSB0. But grub?
– Alessandro Pezzato
Jun 18 '13 at 15:04
You're right. This is obvious. Linux kernel can use it as a serial device through /dev/ttyUSB0. But grub?
– Alessandro Pezzato
Jun 18 '13 at 15:04
1
1
@AlessandroPezzato Even the kernel cannot simply access it as a serial port. It needs to talk to the USB controller. Thus no output is possible until both USB and the adapter driver are available (usually as a module).
– Hauke Laging
Jun 18 '13 at 15:10
@AlessandroPezzato Even the kernel cannot simply access it as a serial port. It needs to talk to the USB controller. Thus no output is possible until both USB and the adapter driver are available (usually as a module).
– Hauke Laging
Jun 18 '13 at 15:10
1
1
Right, kernel uses a module, usally ftdi or prolific. I guess something similar exists for grub.
– Alessandro Pezzato
Jun 18 '13 at 15:18
Right, kernel uses a module, usally ftdi or prolific. I guess something similar exists for grub.
– Alessandro Pezzato
Jun 18 '13 at 15:18
add a comment |Â
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1
might be of interest savannah.gnu.org/bugs/?36740
– frostschutz
Jun 19 '13 at 18:47