commit 8d2f8cd424 breaks parallel port, regression since 3.9-rc3 / backported to stable (3.4.37)

commit 8d2f8cd424 breaks parallel port, regression since 3.9-rc3 / backported to stable (3.4.37)

[Stefan Seyfried]

Hi all,

the following commit:

commit 8d2f8cd424ca0b99001f3ff4f5db87c4e525f366
Author: Wang YanQing <udknight@gmail.com>
Date:   Fri Mar 1 11:47:20 2013 +0800

    serial: 8250_pci: add support for another kind of NetMos Technology PCI 9835 Multi-I/O Controller
    
    01:08.0 Communication controller: NetMos Technology PCI 9835 Multi-I/O Controller (rev 01)
        Subsystem: Device [1000:0012]
        Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Interrupt: pin A routed to IRQ 20
        Region 0: I/O ports at e050 [size=8]
        Region 1: I/O ports at e040 [size=8]
        Region 2: I/O ports at e030 [size=8]
        Region 3: I/O ports at e020 [size=8]
        Region 4: I/O ports at e010 [size=8]
        Region 5: I/O ports at e000 [size=16]
    
    Signed-off-by: Wang YanQing <udknight@gmail.com>
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


breaks my
05:05.0 Communication controller: NetMos Technology PCI 9835 Multi-I/O Controller (rev 01)
05:05.0 0780: 9710:9835 (rev 01)
        Subsystem: 1000:0012

which has two serial and one parallel port, driven by parport_serial.

The reason is, that this commit adds the PCI ID to 8250_pci, when it
was handled by parport_serial before.
In my case (openSUSE kernel), 8250 is built in and parport_serial is
built as a module. Unfortunately with the device occupied by 8250,
parport_serial finds no device and thus does not drive the parport.

I bisected this in the stable series after the openSUSE kernel update
(which pulled in the stable kernel update) broke my printing.

Actually the above commit is totally unnecessary: the serial ports
work very well without it, they are just driven by another driver.

Can this please be reverted? I can't see which problem it solves, but
it definitely breaks the additional ports on my multi-i/o board.

Best regards,

	Stefan
-- 
Stefan Seyfried
Linux Consultant & Developer -- GPG Key: 0x731B665B

B1 Systems GmbH
Osterfeldstraße 7 / 85088 Vohburg / http://www.b1-systems.de
GF: Ralph Dehner / Unternehmenssitz: Vohburg / AG: Ingolstadt,HRB 3537

Re: commit 8d2f8cd424 breaks parallel port, regression since 3.9-rc3 / backported to stable (3.4.37)

[Greg Kroah-Hartman]

On Sun, Jun 30, 2013 at 03:47:44PM +0200, Stefan Seyfried wrote:
> Hi all,
> 
> the following commit:
> 
> commit 8d2f8cd424ca0b99001f3ff4f5db87c4e525f366
> Author: Wang YanQing <udknight@gmail.com>
> Date:   Fri Mar 1 11:47:20 2013 +0800
> 
>     serial: 8250_pci: add support for another kind of NetMos Technology PCI 9835 Multi-I/O Controller
>     
>     01:08.0 Communication controller: NetMos Technology PCI 9835 Multi-I/O Controller (rev 01)
>         Subsystem: Device [1000:0012]
>         Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
>         Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
>         Interrupt: pin A routed to IRQ 20
>         Region 0: I/O ports at e050 [size=8]
>         Region 1: I/O ports at e040 [size=8]
>         Region 2: I/O ports at e030 [size=8]
>         Region 3: I/O ports at e020 [size=8]
>         Region 4: I/O ports at e010 [size=8]
>         Region 5: I/O ports at e000 [size=16]
>     
>     Signed-off-by: Wang YanQing <udknight@gmail.com>
>     Cc: stable <stable@vger.kernel.org>
>     Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> 
> breaks my
> 05:05.0 Communication controller: NetMos Technology PCI 9835 Multi-I/O Controller (rev 01)
> 05:05.0 0780: 9710:9835 (rev 01)
>         Subsystem: 1000:0012
> 
> which has two serial and one parallel port, driven by parport_serial.
> 
> The reason is, that this commit adds the PCI ID to 8250_pci, when it
> was handled by parport_serial before.
> In my case (openSUSE kernel), 8250 is built in and parport_serial is
> built as a module. Unfortunately with the device occupied by 8250,
> parport_serial finds no device and thus does not drive the parport.
> 
> I bisected this in the stable series after the openSUSE kernel update
> (which pulled in the stable kernel update) broke my printing.
> 
> Actually the above commit is totally unnecessary: the serial ports
> work very well without it, they are just driven by another driver.
> 
> Can this please be reverted? I can't see which problem it solves, but
> it definitely breaks the additional ports on my multi-i/o board.

Thanks for pointing this out, I missed the fact that parport_serial was
already controlling this device.  I'll revert it and get it into the
stable trees after it hits Linus's tree (probably next week some time.)

thanks,

greg k-h

8250_pci: improve code comments and Kconfig help

[stefan.seyfried]

Hi Greg,

in order to avoid such regressions in the future, a comment in
the source and a note in the Kconfig help text might be useful

This patch is against
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-next

Best regards,

	Stefan

-- 
Stefan Seyfried
Linux Consultant & Developer -- GPG Key: 0x731B665B

B1 Systems GmbH
Osterfeldstraße 7 / 85088 Vohburg / http://www.b1-systems.de
GF: Ralph Dehner / Unternehmenssitz: Vohburg / AG: Ingolstadt,HRB 3537

[PATCH] 8250_pci: improve code comments and Kconfig help

[stefan.seyfried]

From: Stefan Seyfried <seife+kernel@b1-systems.com>

The recent regression about NetMos 9835 Multi-I/O boards indicates
that comment pointing to the parport_serial driver could be helpful.

Signed-off-by: Stefan Seyfried <seife+kernel@b1-systems.com>
---
 drivers/tty/serial/8250/8250_pci.c | 6 ++++++
 drivers/tty/serial/8250/Kconfig    | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index c52948b..c626c4f 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -4797,6 +4797,12 @@ static struct pci_device_id serial_pci_tbl[] = {
 		PCI_VENDOR_ID_IBM, 0x0299,
 		0, 0, pbn_b0_bt_2_115200 },
 
+	/*
+	 * other NetMos 9835 devices are most likely handled by the
+	 * parport_serial driver, check drivers/parport/parport_serial.c
+	 * before adding them here.
+	 */
+
 	{	PCI_VENDOR_ID_NETMOS, PCI_DEVICE_ID_NETMOS_9901,
 		0xA000, 0x1000,
 		0, 0, pbn_b0_1_115200 },
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index a1ba94d..f3b306e 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -116,6 +116,8 @@ config SERIAL_8250_PCI
 	  This builds standard PCI serial support. You may be able to
 	  disable this feature if you only need legacy serial support.
 	  Saves about 9K.
+	  Note that serial ports on NetMos 9835 Multi-I/O cards are handled
+	  by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
 
 config SERIAL_8250_HP300
 	tristate
-- 
1.8.3.1