serial driver issue

serial driver issue

[Oleksii Hryhorovych]

Hi. I have a problem with linux "serial" driver. I`m using a MosChip
9901 based ExpressCard 34 dual rs-232 controller. When I plugged this
card into my PC, the system detected it, but when I tried to send or
read something from one of the ports, there was silence. Loopback test
also fails. On windows this card works perfectly, so this is not a
hardware issue. My kernel version is "5.15.78-1-MANJARO".

"dmesg" output about this card:

[64329.311478] pcieport 0000:00:1c.1: pciehp: Slot(1): Card present
[64329.311485] pcieport 0000:00:1c.1: pciehp: Slot(1): Link Up
[64329.442833] pci 0000:02:00.0: [9710:9901] type 00 class 0x070002
[64329.442867] pci 0000:02:00.0: reg 0x10: [io  0x0000-0x0007]
[64329.442883] pci 0000:02:00.0: reg 0x14: [mem 0x00000000-0x00000fff]
[64329.442922] pci 0000:02:00.0: reg 0x20: [mem 0x00000000-0x00000fff]
[64329.443096] pci 0000:02:00.0: supports D1 D2
[64329.443099] pci 0000:02:00.0: PME# supported from D0 D1 D2 D3hot D3cold
[64329.443402] pci 0000:02:00.1: [9710:9901] type 00 class 0x070002
[64329.443434] pci 0000:02:00.1: reg 0x10: [io  0x0000-0x0007]
[64329.443451] pci 0000:02:00.1: reg 0x14: [mem 0x00000000-0x00000fff]
[64329.443495] pci 0000:02:00.1: reg 0x20: [mem 0x00000000-0x00000fff]
[64329.443679] pci 0000:02:00.1: supports D1 D2
[64329.443683] pci 0000:02:00.1: PME# supported from D0 D1 D2 D3hot D3cold
[64329.443948] pci 0000:02:00.0: BAR 1: assigned [mem 0xd0000000-0xd0000fff]
[64329.443960] pci 0000:02:00.0: BAR 4: assigned [mem 0xd0001000-0xd0001fff]
[64329.443969] pci 0000:02:00.1: BAR 1: assigned [mem 0xd0002000-0xd0002fff]
[64329.443979] pci 0000:02:00.1: BAR 4: assigned [mem 0xd0003000-0xd0003fff]
[64329.443987] pci 0000:02:00.0: BAR 0: assigned [io  0x2000-0x2007]
[64329.443995] pci 0000:02:00.1: BAR 0: assigned [io  0x2008-0x200f]
[64329.444006] pcieport 0000:00:1c.1: PCI bridge to [bus 02-22]
[64329.444012] pcieport 0000:00:1c.1:   bridge window [io  0x2000-0x3fff]
[64329.444017] pcieport 0000:00:1c.1:   bridge window [mem
0xd0000000-0xd3ffffff]
[64329.444023] pcieport 0000:00:1c.1:   bridge window [mem
0xbfb00000-0xbfcfffff 64bit pref]
[64329.444110] serial 0000:02:00.0: enabling device (0000 -> 0003)
[64329.444690] 0000:02:00.0: ttyS6 at I/O 0x2000 (irq = 17, base_baud
= 115200) is a 16550A
[64329.448040] serial 0000:02:00.1: enabling device (0000 -> 0003)
[64329.452843] 0000:02:00.1: ttyS7 at I/O 0x2008 (irq = 18, base_baud
= 115200) is a 16550A

"lspci -vvv" output about this card:

02:00.0 Serial controller: MosChip Semiconductor Technology Ltd. PCIe
9901 Multi-I/O Controller (prog-if 02 [16550])
       Subsystem: Asix Electronics Corporation (Wrong ID) Device 1000
       Physical Slot: 1
       Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR- FastB2B- DisINTx-
       Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
       Interrupt: pin A routed to IRQ 17
       Region 0: I/O ports at 2000 [size=8]
       Region 1: Memory at d0000000 (32-bit, non-prefetchable) [size=4K]
       Region 4: Memory at d0001000 (32-bit, non-prefetchable) [size=4K]
       Capabilities: [80] Power Management version 3
               Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA
PME(D0+,D1+,D2+,D3hot+,D3cold+)
               Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=1 PME-
       Capabilities: [88] MSI: Enable- Count=1/32 Maskable- 64bit+
               Address: 0000000000000000  Data: 0000
       Capabilities: [c0] Express (v1) Legacy Endpoint, MSI 00
               DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s
<64ns, L1 <1us
                       ExtTag- AttnBtn+ AttnInd+ PwrInd+ RBE- FLReset-
               DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
                       RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
                       MaxPayload 128 bytes, MaxReadReq 512 bytes
               DevSta: CorrErr- NonFatalErr+ FatalErr- UnsupReq+
AuxPwr- TransPend-
               LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1,
Exit Latency L0s unlimited, L1 unlimited
                       ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp-
               LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk+
                       ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
               LnkSta: Speed 2.5GT/s, Width x1
                       TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
       Capabilities: [100 v1] Power Budgeting <?>
       Capabilities: [200 v1] Device Serial Number 88-99-ff-ee-dd-cc-bb-aa
       Kernel driver in use: serial

02:00.1 Serial controller: MosChip Semiconductor Technology Ltd. PCIe
9901 Multi-I/O Controller (prog-if 02 [16550])
       Subsystem: Asix Electronics Corporation (Wrong ID) Device 1000
       Physical Slot: 1
       Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR- FastB2B- DisINTx-
       Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
       Interrupt: pin B routed to IRQ 18
       Region 0: I/O ports at 2008 [size=8]
       Region 1: Memory at d0002000 (32-bit, non-prefetchable) [size=4K]
       Region 4: Memory at d0003000 (32-bit, non-prefetchable) [size=4K]
       Capabilities: [80] Power Management version 3
               Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA
PME(D0+,D1+,D2+,D3hot+,D3cold+)
               Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=1 PME-
       Capabilities: [88] MSI: Enable- Count=1/32 Maskable- 64bit+
               Address: 0000000000000000  Data: 0000
       Capabilities: [c0] Express (v1) Legacy Endpoint, MSI 00
               DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s
<64ns, L1 <1us
                       ExtTag- AttnBtn+ AttnInd+ PwrInd+ RBE- FLReset-
               DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
                       RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
                       MaxPayload 128 bytes, MaxReadReq 512 bytes
               DevSta: CorrErr- NonFatalErr+ FatalErr- UnsupReq+
AuxPwr- TransPend-
               LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1,
Exit Latency L0s unlimited, L1 unlimited
                       ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp-
               LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk+
                       ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
               LnkSta: Speed 2.5GT/s, Width x1
                       TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
       Capabilities: [100 v1] Power Budgeting <?>
       Capabilities: [200 v1] Device Serial Number 00-00-00-00-00-00-00-00
       Kernel driver in use: serial

Re: serial driver issue

[Greg KH]

On Sun, Dec 04, 2022 at 06:42:19PM +0200, Oleksii Hryhorovych wrote:
> Hi. I have a problem with linux "serial" driver. I`m using a MosChip
> 9901 based ExpressCard 34 dual rs-232 controller. When I plugged this
> card into my PC, the system detected it, but when I tried to send or
> read something from one of the ports, there was silence. Loopback test
> also fails. On windows this card works perfectly, so this is not a
> hardware issue. My kernel version is "5.15.78-1-MANJARO".

How exactly are you trying to send data through the port?  What command
did you use and what was the result?


> 
> "dmesg" output about this card:
> 
> [64329.311478] pcieport 0000:00:1c.1: pciehp: Slot(1): Card present
> [64329.311485] pcieport 0000:00:1c.1: pciehp: Slot(1): Link Up
> [64329.442833] pci 0000:02:00.0: [9710:9901] type 00 class 0x070002
> [64329.442867] pci 0000:02:00.0: reg 0x10: [io  0x0000-0x0007]
> [64329.442883] pci 0000:02:00.0: reg 0x14: [mem 0x00000000-0x00000fff]
> [64329.442922] pci 0000:02:00.0: reg 0x20: [mem 0x00000000-0x00000fff]
> [64329.443096] pci 0000:02:00.0: supports D1 D2
> [64329.443099] pci 0000:02:00.0: PME# supported from D0 D1 D2 D3hot D3cold
> [64329.443402] pci 0000:02:00.1: [9710:9901] type 00 class 0x070002
> [64329.443434] pci 0000:02:00.1: reg 0x10: [io  0x0000-0x0007]
> [64329.443451] pci 0000:02:00.1: reg 0x14: [mem 0x00000000-0x00000fff]
> [64329.443495] pci 0000:02:00.1: reg 0x20: [mem 0x00000000-0x00000fff]
> [64329.443679] pci 0000:02:00.1: supports D1 D2
> [64329.443683] pci 0000:02:00.1: PME# supported from D0 D1 D2 D3hot D3cold
> [64329.443948] pci 0000:02:00.0: BAR 1: assigned [mem 0xd0000000-0xd0000fff]
> [64329.443960] pci 0000:02:00.0: BAR 4: assigned [mem 0xd0001000-0xd0001fff]
> [64329.443969] pci 0000:02:00.1: BAR 1: assigned [mem 0xd0002000-0xd0002fff]
> [64329.443979] pci 0000:02:00.1: BAR 4: assigned [mem 0xd0003000-0xd0003fff]
> [64329.443987] pci 0000:02:00.0: BAR 0: assigned [io  0x2000-0x2007]
> [64329.443995] pci 0000:02:00.1: BAR 0: assigned [io  0x2008-0x200f]
> [64329.444006] pcieport 0000:00:1c.1: PCI bridge to [bus 02-22]
> [64329.444012] pcieport 0000:00:1c.1:   bridge window [io  0x2000-0x3fff]
> [64329.444017] pcieport 0000:00:1c.1:   bridge window [mem
> 0xd0000000-0xd3ffffff]
> [64329.444023] pcieport 0000:00:1c.1:   bridge window [mem
> 0xbfb00000-0xbfcfffff 64bit pref]
> [64329.444110] serial 0000:02:00.0: enabling device (0000 -> 0003)
> [64329.444690] 0000:02:00.0: ttyS6 at I/O 0x2000 (irq = 17, base_baud
> = 115200) is a 16550A
> [64329.448040] serial 0000:02:00.1: enabling device (0000 -> 0003)
> [64329.452843] 0000:02:00.1: ttyS7 at I/O 0x2008 (irq = 18, base_baud
> = 115200) is a 16550A


Which tty device node are you using here?

What does the output of `find /dev/serial/` show?

thanks,

greg k-h

Re: serial driver issue

[Oleksii Hryhorovych]

вс, 4 дек. 2022 г. в 18:53, Greg KH <gregkh@linuxfoundation.org>:
>
> On Sun, Dec 04, 2022 at 06:42:19PM +0200, Oleksii Hryhorovych wrote:
> > Hi. I have a problem with linux "serial" driver. I`m using a MosChip
> > 9901 based ExpressCard 34 dual rs-232 controller. When I plugged this
> > card into my PC, the system detected it, but when I tried to send or
> > read something from one of the ports, there was silence. Loopback test
> > also fails. On windows this card works perfectly, so this is not a
> > hardware issue. My kernel version is "5.15.78-1-MANJARO".
>
> How exactly are you trying to send data through the port?  What command
> did you use and what was the result?
>
I tried(each test 4 times, trying each device node for each port):
1) Execute "cat /dev/ttyS6"(or ttyS7), connect rs-232 cable to port on
the card and to another PC, then send from another PC something to
port.
Result: nothing new appeared in console
2) Connect rs232 cable to port on card and to another PC. Run terminal
on another PC, run minicom on this PC. Disable flow control. Send
something to terminal on both PCs.
Result: nothing appeared in terminals on both PCs.
3) Connect pins number 2 and 3 on rs232 port (loopback test). Open
minicom, disable flow control and send something to the terminal.
Result: nothing new appeared in the terminal
4) Connect pins number 2 and 3 on rs232 port (loopback test). Open
first console window, run "cat /dev/ttyS6"(or ttyS7). Open second
window, run "echo "test" > /dev/ttyS6"(or ttyS7).
Result: nothing new appeared in the first console
>
> >
> > "dmesg" output about this card:
> >
> > [64329.311478] pcieport 0000:00:1c.1: pciehp: Slot(1): Card present
> > [64329.311485] pcieport 0000:00:1c.1: pciehp: Slot(1): Link Up
> > [64329.442833] pci 0000:02:00.0: [9710:9901] type 00 class 0x070002
> > [64329.442867] pci 0000:02:00.0: reg 0x10: [io  0x0000-0x0007]
> > [64329.442883] pci 0000:02:00.0: reg 0x14: [mem 0x00000000-0x00000fff]
> > [64329.442922] pci 0000:02:00.0: reg 0x20: [mem 0x00000000-0x00000fff]
> > [64329.443096] pci 0000:02:00.0: supports D1 D2
> > [64329.443099] pci 0000:02:00.0: PME# supported from D0 D1 D2 D3hot D3cold
> > [64329.443402] pci 0000:02:00.1: [9710:9901] type 00 class 0x070002
> > [64329.443434] pci 0000:02:00.1: reg 0x10: [io  0x0000-0x0007]
> > [64329.443451] pci 0000:02:00.1: reg 0x14: [mem 0x00000000-0x00000fff]
> > [64329.443495] pci 0000:02:00.1: reg 0x20: [mem 0x00000000-0x00000fff]
> > [64329.443679] pci 0000:02:00.1: supports D1 D2
> > [64329.443683] pci 0000:02:00.1: PME# supported from D0 D1 D2 D3hot D3cold
> > [64329.443948] pci 0000:02:00.0: BAR 1: assigned [mem 0xd0000000-0xd0000fff]
> > [64329.443960] pci 0000:02:00.0: BAR 4: assigned [mem 0xd0001000-0xd0001fff]
> > [64329.443969] pci 0000:02:00.1: BAR 1: assigned [mem 0xd0002000-0xd0002fff]
> > [64329.443979] pci 0000:02:00.1: BAR 4: assigned [mem 0xd0003000-0xd0003fff]
> > [64329.443987] pci 0000:02:00.0: BAR 0: assigned [io  0x2000-0x2007]
> > [64329.443995] pci 0000:02:00.1: BAR 0: assigned [io  0x2008-0x200f]
> > [64329.444006] pcieport 0000:00:1c.1: PCI bridge to [bus 02-22]
> > [64329.444012] pcieport 0000:00:1c.1:   bridge window [io  0x2000-0x3fff]
> > [64329.444017] pcieport 0000:00:1c.1:   bridge window [mem
> > 0xd0000000-0xd3ffffff]
> > [64329.444023] pcieport 0000:00:1c.1:   bridge window [mem
> > 0xbfb00000-0xbfcfffff 64bit pref]
> > [64329.444110] serial 0000:02:00.0: enabling device (0000 -> 0003)
> > [64329.444690] 0000:02:00.0: ttyS6 at I/O 0x2000 (irq = 17, base_baud
> > = 115200) is a 16550A
> > [64329.448040] serial 0000:02:00.1: enabling device (0000 -> 0003)
> > [64329.452843] 0000:02:00.1: ttyS7 at I/O 0x2008 (irq = 18, base_baud
> > = 115200) is a 16550A
>
>
> Which tty device node are you using here?
>
I tried using both nodes, /dev/ttyS6 and /dev/ttyS7, and the result
was the same.
> What does the output of `find /dev/serial/` show?
>
/dev/serial/
/dev/serial/by-id
/dev/serial/by-id/usb-HP_HP_hs2340_HSPA+_MobileBroadband_C69366190FA2EB60-if01
/dev/serial/by-id/usb-HP_HP_hs2340_HSPA+_MobileBroadband_C69366190FA2EB60-if03
/dev/serial/by-id/usb-HP_HP_hs2340_HSPA+_MobileBroadband_C69366190FA2EB60-if09
/dev/serial/by-path
/dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.9
/dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.1
/dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.3

And it doesn't changes when I remove or insert back this card.
> thanks,
>
> greg k-h

Re: serial driver issue

[Greg KH]

On Sun, Dec 04, 2022 at 08:11:11PM +0200, Oleksii Hryhorovych wrote:
> вс, 4 дек. 2022 г. в 18:53, Greg KH <gregkh@linuxfoundation.org>:
> >
> > On Sun, Dec 04, 2022 at 06:42:19PM +0200, Oleksii Hryhorovych wrote:
> > > Hi. I have a problem with linux "serial" driver. I`m using a MosChip
> > > 9901 based ExpressCard 34 dual rs-232 controller. When I plugged this
> > > card into my PC, the system detected it, but when I tried to send or
> > > read something from one of the ports, there was silence. Loopback test
> > > also fails. On windows this card works perfectly, so this is not a
> > > hardware issue. My kernel version is "5.15.78-1-MANJARO".
> >
> > How exactly are you trying to send data through the port?  What command
> > did you use and what was the result?
> >
> I tried(each test 4 times, trying each device node for each port):
> 1) Execute "cat /dev/ttyS6"(or ttyS7), connect rs-232 cable to port on
> the card and to another PC, then send from another PC something to
> port.
> Result: nothing new appeared in console

"cat" isn't the best test, minicom is good, as you tried:

> 2) Connect rs232 cable to port on card and to another PC. Run terminal
> on another PC, run minicom on this PC. Disable flow control. Send
> something to terminal on both PCs.
> Result: nothing appeared in terminals on both PCs.
> 3) Connect pins number 2 and 3 on rs232 port (loopback test). Open
> minicom, disable flow control and send something to the terminal.
> Result: nothing new appeared in the terminal
> 4) Connect pins number 2 and 3 on rs232 port (loopback test). Open
> first console window, run "cat /dev/ttyS6"(or ttyS7). Open second
> window, run "echo "test" > /dev/ttyS6"(or ttyS7).
> Result: nothing new appeared in the first console

I think the problem is that you do not have a driver attached to your
serial ports, because:

> > > "dmesg" output about this card:
> > >
> > > [64329.311478] pcieport 0000:00:1c.1: pciehp: Slot(1): Card present
> > > [64329.311485] pcieport 0000:00:1c.1: pciehp: Slot(1): Link Up
> > > [64329.442833] pci 0000:02:00.0: [9710:9901] type 00 class 0x070002
> > > [64329.442867] pci 0000:02:00.0: reg 0x10: [io  0x0000-0x0007]
> > > [64329.442883] pci 0000:02:00.0: reg 0x14: [mem 0x00000000-0x00000fff]
> > > [64329.442922] pci 0000:02:00.0: reg 0x20: [mem 0x00000000-0x00000fff]
> > > [64329.443096] pci 0000:02:00.0: supports D1 D2
> > > [64329.443099] pci 0000:02:00.0: PME# supported from D0 D1 D2 D3hot D3cold
> > > [64329.443402] pci 0000:02:00.1: [9710:9901] type 00 class 0x070002
> > > [64329.443434] pci 0000:02:00.1: reg 0x10: [io  0x0000-0x0007]
> > > [64329.443451] pci 0000:02:00.1: reg 0x14: [mem 0x00000000-0x00000fff]
> > > [64329.443495] pci 0000:02:00.1: reg 0x20: [mem 0x00000000-0x00000fff]
> > > [64329.443679] pci 0000:02:00.1: supports D1 D2
> > > [64329.443683] pci 0000:02:00.1: PME# supported from D0 D1 D2 D3hot D3cold
> > > [64329.443948] pci 0000:02:00.0: BAR 1: assigned [mem 0xd0000000-0xd0000fff]
> > > [64329.443960] pci 0000:02:00.0: BAR 4: assigned [mem 0xd0001000-0xd0001fff]
> > > [64329.443969] pci 0000:02:00.1: BAR 1: assigned [mem 0xd0002000-0xd0002fff]
> > > [64329.443979] pci 0000:02:00.1: BAR 4: assigned [mem 0xd0003000-0xd0003fff]
> > > [64329.443987] pci 0000:02:00.0: BAR 0: assigned [io  0x2000-0x2007]
> > > [64329.443995] pci 0000:02:00.1: BAR 0: assigned [io  0x2008-0x200f]
> > > [64329.444006] pcieport 0000:00:1c.1: PCI bridge to [bus 02-22]
> > > [64329.444012] pcieport 0000:00:1c.1:   bridge window [io  0x2000-0x3fff]
> > > [64329.444017] pcieport 0000:00:1c.1:   bridge window [mem
> > > 0xd0000000-0xd3ffffff]
> > > [64329.444023] pcieport 0000:00:1c.1:   bridge window [mem
> > > 0xbfb00000-0xbfcfffff 64bit pref]
> > > [64329.444110] serial 0000:02:00.0: enabling device (0000 -> 0003)
> > > [64329.444690] 0000:02:00.0: ttyS6 at I/O 0x2000 (irq = 17, base_baud
> > > = 115200) is a 16550A
> > > [64329.448040] serial 0000:02:00.1: enabling device (0000 -> 0003)
> > > [64329.452843] 0000:02:00.1: ttyS7 at I/O 0x2008 (irq = 18, base_baud
> > > = 115200) is a 16550A

ttyS6 and ttyS7 seem to be the correct devices, but:

> > Which tty device node are you using here?
> >
> I tried using both nodes, /dev/ttyS6 and /dev/ttyS7, and the result
> was the same.
> > What does the output of `find /dev/serial/` show?
> >
> /dev/serial/
> /dev/serial/by-id
> /dev/serial/by-id/usb-HP_HP_hs2340_HSPA+_MobileBroadband_C69366190FA2EB60-if01
> /dev/serial/by-id/usb-HP_HP_hs2340_HSPA+_MobileBroadband_C69366190FA2EB60-if03
> /dev/serial/by-id/usb-HP_HP_hs2340_HSPA+_MobileBroadband_C69366190FA2EB60-if09
> /dev/serial/by-path
> /dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.9
> /dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.1
> /dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.3

You only have usb-serial devices seen in the system.

Are you sure the PCI card is being controlled properly?  No other kernel
log messages?

Is /dev/ttyS6 and ttyS7 present in /dev?

What does 'ls -l /sys/class/tty/' show?

thanks,

greg k-h

Re: serial driver issue

[Oleksii Hryhorovych]

пн, 5 дек. 2022 г. в 17:19, Greg KH <gregkh@linuxfoundation.org>:
>
> On Sun, Dec 04, 2022 at 08:11:11PM +0200, Oleksii Hryhorovych wrote:
> > вс, 4 дек. 2022 г. в 18:53, Greg KH <gregkh@linuxfoundation.org>:
> > >
> > > On Sun, Dec 04, 2022 at 06:42:19PM +0200, Oleksii Hryhorovych wrote:
> > > > Hi. I have a problem with linux "serial" driver. I`m using a MosChip
> > > > 9901 based ExpressCard 34 dual rs-232 controller. When I plugged this
> > > > card into my PC, the system detected it, but when I tried to send or
> > > > read something from one of the ports, there was silence. Loopback test
> > > > also fails. On windows this card works perfectly, so this is not a
> > > > hardware issue. My kernel version is "5.15.78-1-MANJARO".
> > >
> > > How exactly are you trying to send data through the port?  What command
> > > did you use and what was the result?
> > >
> > I tried(each test 4 times, trying each device node for each port):
> > 1) Execute "cat /dev/ttyS6"(or ttyS7), connect rs-232 cable to port on
> > the card and to another PC, then send from another PC something to
> > port.
> > Result: nothing new appeared in console
>
> "cat" isn't the best test, minicom is good, as you tried:
>
> > 2) Connect rs232 cable to port on card and to another PC. Run terminal
> > on another PC, run minicom on this PC. Disable flow control. Send
> > something to terminal on both PCs.
> > Result: nothing appeared in terminals on both PCs.
> > 3) Connect pins number 2 and 3 on rs232 port (loopback test). Open
> > minicom, disable flow control and send something to the terminal.
> > Result: nothing new appeared in the terminal
> > 4) Connect pins number 2 and 3 on rs232 port (loopback test). Open
> > first console window, run "cat /dev/ttyS6"(or ttyS7). Open second
> > window, run "echo "test" > /dev/ttyS6"(or ttyS7).
> > Result: nothing new appeared in the first console
>
> I think the problem is that you do not have a driver attached to your
> serial ports, because:
>
> > > > "dmesg" output about this card:
> > > >
> > > > [64329.311478] pcieport 0000:00:1c.1: pciehp: Slot(1): Card present
> > > > [64329.311485] pcieport 0000:00:1c.1: pciehp: Slot(1): Link Up
> > > > [64329.442833] pci 0000:02:00.0: [9710:9901] type 00 class 0x070002
> > > > [64329.442867] pci 0000:02:00.0: reg 0x10: [io  0x0000-0x0007]
> > > > [64329.442883] pci 0000:02:00.0: reg 0x14: [mem 0x00000000-0x00000fff]
> > > > [64329.442922] pci 0000:02:00.0: reg 0x20: [mem 0x00000000-0x00000fff]
> > > > [64329.443096] pci 0000:02:00.0: supports D1 D2
> > > > [64329.443099] pci 0000:02:00.0: PME# supported from D0 D1 D2 D3hot D3cold
> > > > [64329.443402] pci 0000:02:00.1: [9710:9901] type 00 class 0x070002
> > > > [64329.443434] pci 0000:02:00.1: reg 0x10: [io  0x0000-0x0007]
> > > > [64329.443451] pci 0000:02:00.1: reg 0x14: [mem 0x00000000-0x00000fff]
> > > > [64329.443495] pci 0000:02:00.1: reg 0x20: [mem 0x00000000-0x00000fff]
> > > > [64329.443679] pci 0000:02:00.1: supports D1 D2
> > > > [64329.443683] pci 0000:02:00.1: PME# supported from D0 D1 D2 D3hot D3cold
> > > > [64329.443948] pci 0000:02:00.0: BAR 1: assigned [mem 0xd0000000-0xd0000fff]
> > > > [64329.443960] pci 0000:02:00.0: BAR 4: assigned [mem 0xd0001000-0xd0001fff]
> > > > [64329.443969] pci 0000:02:00.1: BAR 1: assigned [mem 0xd0002000-0xd0002fff]
> > > > [64329.443979] pci 0000:02:00.1: BAR 4: assigned [mem 0xd0003000-0xd0003fff]
> > > > [64329.443987] pci 0000:02:00.0: BAR 0: assigned [io  0x2000-0x2007]
> > > > [64329.443995] pci 0000:02:00.1: BAR 0: assigned [io  0x2008-0x200f]
> > > > [64329.444006] pcieport 0000:00:1c.1: PCI bridge to [bus 02-22]
> > > > [64329.444012] pcieport 0000:00:1c.1:   bridge window [io  0x2000-0x3fff]
> > > > [64329.444017] pcieport 0000:00:1c.1:   bridge window [mem
> > > > 0xd0000000-0xd3ffffff]
> > > > [64329.444023] pcieport 0000:00:1c.1:   bridge window [mem
> > > > 0xbfb00000-0xbfcfffff 64bit pref]
> > > > [64329.444110] serial 0000:02:00.0: enabling device (0000 -> 0003)
> > > > [64329.444690] 0000:02:00.0: ttyS6 at I/O 0x2000 (irq = 17, base_baud
> > > > = 115200) is a 16550A
> > > > [64329.448040] serial 0000:02:00.1: enabling device (0000 -> 0003)
> > > > [64329.452843] 0000:02:00.1: ttyS7 at I/O 0x2008 (irq = 18, base_baud
> > > > = 115200) is a 16550A
>
> ttyS6 and ttyS7 seem to be the correct devices, but:
>
> > > Which tty device node are you using here?
> > >
> > I tried using both nodes, /dev/ttyS6 and /dev/ttyS7, and the result
> > was the same.
> > > What does the output of `find /dev/serial/` show?
> > >
> > /dev/serial/
> > /dev/serial/by-id
> > /dev/serial/by-id/usb-HP_HP_hs2340_HSPA+_MobileBroadband_C69366190FA2EB60-if01
> > /dev/serial/by-id/usb-HP_HP_hs2340_HSPA+_MobileBroadband_C69366190FA2EB60-if03
> > /dev/serial/by-id/usb-HP_HP_hs2340_HSPA+_MobileBroadband_C69366190FA2EB60-if09
> > /dev/serial/by-path
> > /dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.9
> > /dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.1
> > /dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.3
>
> You only have usb-serial devices seen in the system.
>
> Are you sure the PCI card is being controlled properly?  No other kernel
> log messages?

I'm not sure about it, because I haven't proof of it. But there are no
other kernel messages about this card, and no errors in general.

>
> Is /dev/ttyS6 and ttyS7 present in /dev?

Yes.

>
> What does 'ls -l /sys/class/tty/' show?

lrwxrwxrwx 1 root root 0 дек  2 15:03 console ->
../../devices/virtual/tty/console
lrwxrwxrwx 1 root root 0 дек  2 15:03 ptmx -> ../../devices/virtual/tty/ptmx
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty -> ../../devices/virtual/tty/tty
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty0 -> ../../devices/virtual/tty/tty0
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty1 -> ../../devices/virtual/tty/tty1
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty10 -> ../../devices/virtual/tty/tty10
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty11 -> ../../devices/virtual/tty/tty11
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty12 -> ../../devices/virtual/tty/tty12
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty13 -> ../../devices/virtual/tty/tty13
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty14 -> ../../devices/virtual/tty/tty14
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty15 -> ../../devices/virtual/tty/tty15
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty16 -> ../../devices/virtual/tty/tty16
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty17 -> ../../devices/virtual/tty/tty17
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty18 -> ../../devices/virtual/tty/tty18
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty19 -> ../../devices/virtual/tty/tty19
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty2 -> ../../devices/virtual/tty/tty2
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty20 -> ../../devices/virtual/tty/tty20
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty21 -> ../../devices/virtual/tty/tty21
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty22 -> ../../devices/virtual/tty/tty22
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty23 -> ../../devices/virtual/tty/tty23
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty24 -> ../../devices/virtual/tty/tty24
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty25 -> ../../devices/virtual/tty/tty25
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty26 -> ../../devices/virtual/tty/tty26
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty27 -> ../../devices/virtual/tty/tty27
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty28 -> ../../devices/virtual/tty/tty28
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty29 -> ../../devices/virtual/tty/tty29
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty3 -> ../../devices/virtual/tty/tty3
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty30 -> ../../devices/virtual/tty/tty30
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty31 -> ../../devices/virtual/tty/tty31
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty32 -> ../../devices/virtual/tty/tty32
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty33 -> ../../devices/virtual/tty/tty33
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty34 -> ../../devices/virtual/tty/tty34
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty35 -> ../../devices/virtual/tty/tty35
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty36 -> ../../devices/virtual/tty/tty36
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty37 -> ../../devices/virtual/tty/tty37
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty38 -> ../../devices/virtual/tty/tty38
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty39 -> ../../devices/virtual/tty/tty39
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty4 -> ../../devices/virtual/tty/tty4
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty40 -> ../../devices/virtual/tty/tty40
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty41 -> ../../devices/virtual/tty/tty41
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty42 -> ../../devices/virtual/tty/tty42
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty43 -> ../../devices/virtual/tty/tty43
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty44 -> ../../devices/virtual/tty/tty44
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty45 -> ../../devices/virtual/tty/tty45
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty46 -> ../../devices/virtual/tty/tty46
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty47 -> ../../devices/virtual/tty/tty47
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty48 -> ../../devices/virtual/tty/tty48
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty49 -> ../../devices/virtual/tty/tty49
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty5 -> ../../devices/virtual/tty/tty5
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty50 -> ../../devices/virtual/tty/tty50
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty51 -> ../../devices/virtual/tty/tty51
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty52 -> ../../devices/virtual/tty/tty52
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty53 -> ../../devices/virtual/tty/tty53
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty54 -> ../../devices/virtual/tty/tty54
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty55 -> ../../devices/virtual/tty/tty55
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty56 -> ../../devices/virtual/tty/tty56
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty57 -> ../../devices/virtual/tty/tty57
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty58 -> ../../devices/virtual/tty/tty58
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty59 -> ../../devices/virtual/tty/tty59
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty6 -> ../../devices/virtual/tty/tty6
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty60 -> ../../devices/virtual/tty/tty60
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty61 -> ../../devices/virtual/tty/tty61
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty62 -> ../../devices/virtual/tty/tty62
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty63 -> ../../devices/virtual/tty/tty63
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty7 -> ../../devices/virtual/tty/tty7
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty8 -> ../../devices/virtual/tty/tty8
lrwxrwxrwx 1 root root 0 дек  2 15:03 tty9 -> ../../devices/virtual/tty/tty9
lrwxrwxrwx 1 root root 0 дек  2 16:19 ttyACM0 ->
../../devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.2/1-1.2:1.1/tty/ttyACM0
lrwxrwxrwx 1 root root 0 дек  2 16:19 ttyACM1 ->
../../devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.2/1-1.2:1.3/tty/ttyACM1
lrwxrwxrwx 1 root root 0 дек  2 16:19 ttyACM2 ->
../../devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.2/1-1.2:1.9/tty/ttyACM2
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS0 ->
../../devices/platform/serial8250/tty/ttyS0
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS1 ->
../../devices/platform/serial8250/tty/ttyS1
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS10 ->
../../devices/platform/serial8250/tty/ttyS10
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS11 ->
../../devices/platform/serial8250/tty/ttyS11
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS12 ->
../../devices/platform/serial8250/tty/ttyS12
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS13 ->
../../devices/platform/serial8250/tty/ttyS13
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS14 ->
../../devices/platform/serial8250/tty/ttyS14
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS15 ->
../../devices/platform/serial8250/tty/ttyS15
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS16 ->
../../devices/platform/serial8250/tty/ttyS16
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS17 ->
../../devices/platform/serial8250/tty/ttyS17
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS18 ->
../../devices/platform/serial8250/tty/ttyS18
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS19 ->
../../devices/platform/serial8250/tty/ttyS19
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS2 ->
../../devices/platform/serial8250/tty/ttyS2
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS20 ->
../../devices/platform/serial8250/tty/ttyS20
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS21 ->
../../devices/platform/serial8250/tty/ttyS21
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS22 ->
../../devices/platform/serial8250/tty/ttyS22
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS23 ->
../../devices/platform/serial8250/tty/ttyS23
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS24 ->
../../devices/platform/serial8250/tty/ttyS24
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS25 ->
../../devices/platform/serial8250/tty/ttyS25
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS26 ->
../../devices/platform/serial8250/tty/ttyS26
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS27 ->
../../devices/platform/serial8250/tty/ttyS27
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS28 ->
../../devices/platform/serial8250/tty/ttyS28
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS29 ->
../../devices/platform/serial8250/tty/ttyS29
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS3 ->
../../devices/platform/serial8250/tty/ttyS3
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS30 ->
../../devices/platform/serial8250/tty/ttyS30
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS31 ->
../../devices/platform/serial8250/tty/ttyS31
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS4 ->
../../devices/pnp0/00:04/tty/ttyS4
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS5 ->
../../devices/pci0000:00/0000:00:16.3/tty/ttyS5
lrwxrwxrwx 1 root root 0 дек  5 18:50 ttyS6 ->
../../devices/pci0000:00/0000:00:1c.1/0000:02:00.0/tty/ttyS6
lrwxrwxrwx 1 root root 0 дек  5 18:50 ttyS7 ->
../../devices/pci0000:00/0000:00:1c.1/0000:02:00.1/tty/ttyS7
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS8 ->
../../devices/platform/serial8250/tty/ttyS8
lrwxrwxrwx 1 root root 0 дек  2 15:03 ttyS9 ->
../../devices/platform/serial8250/tty/ttyS9

>
> thanks,
>
> greg k-h