Mainpine IQ Express Rev3 problems beginning 2.6.36

Mainpine IQ Express Rev3 problems beginning 2.6.36

[Lee Howard]

Hello everyone,

A week ago I had a customer report to me that they were having problems 
using the Mainpine IQ Express Rev3 (multiport modem which uses the 
Oxsemi OXPCIe95x chipset) after updating their system from kernel 
2.6.22.10 (which they patched because native support for the IQ Express 
didn't enter the kernel until 2.6.28) to kernel 2.6.36.

As I had never used any 2.6.36 kernel, myself, I explained that I had 
experienced no problem with the 2.6.35.6 kernel (as found in Fedora 14) 
at which point they installed kernel 2.6.35.8 and reported back that 
this had resolved the problem for them.

Following their report I then tested by installing the 2.6.37-rc4 kernel 
(using 'make oldconfig', taking .config from the Fedora 14 kernel that 
was working), and I was quickly able to determine that there were 
problems because simple communications with the modems were not working 
properly using 'minicom'.  (I also have now tested with 2.6.37-rc5 with 
the same result.)  Characters appear to be getting lost/dropped in the 
communication... for example, I *expect* the following on the minicom 
terminal screen when I start it up as it initializes the modem:

-------------------
AT S7=45 S0=0 L1 V1 X4 &c1 E1 
Q0                                                           
OK                                                                                          

-------------------

The blinking cursor will be on the line following the OK.  This is what 
happens when using kernel 2.6.35.  However, when I use 2.6.37-rc5 this 
is what I see:

-------------------
AT S7=45 S0=0 L1
-------------------

Sometimes there is a character or two more on the screen but there will 
be no OK and the cursor will be blinking at the end of the line of 
commands... which leads me to believe that the modem did not see the 
CR+LF from the application.  If I simply press enter on the terminal, 
then I'll see the OK as expected.  So it seems to me that only the first 
bunch of characters are making it through and that the rest are getting 
dropped for some reason.

setserial tells me the following about the port:

# setserial -G /dev/ttyS4
/dev/ttyS4 uart 16950/954 port 0x0000 irq 18 baud_base 4000000 
spd_normal skip_test

I think I can say with confidence that the problem started with 2.6.36.

What can I do to help solve the problem?

Thanks,

Lee.

-- 
*Lee Howard*
*Mainpine, Inc. Software Development Lead*
Tel: +1 866 363 6680 | Fax: +1 360 462 8160
lee.howard@mainpine.com | www.mainpine.com

Re: Mainpine IQ Express Rev3 problems beginning 2.6.36

[Greg KH]

On Wed, Dec 08, 2010 at 03:55:29PM -0800, Lee Howard wrote:
> Hello everyone,
> 
> A week ago I had a customer report to me that they were having
> problems using the Mainpine IQ Express Rev3 (multiport modem which
> uses the Oxsemi OXPCIe95x chipset) after updating their system from
> kernel 2.6.22.10 (which they patched because native support for the
> IQ Express didn't enter the kernel until 2.6.28) to kernel 2.6.36.
> 
> As I had never used any 2.6.36 kernel, myself, I explained that I
> had experienced no problem with the 2.6.35.6 kernel (as found in
> Fedora 14) at which point they installed kernel 2.6.35.8 and
> reported back that this had resolved the problem for them.
> 
> Following their report I then tested by installing the 2.6.37-rc4
> kernel (using 'make oldconfig', taking .config from the Fedora 14
> kernel that was working), and I was quickly able to determine that
> there were problems because simple communications with the modems
> were not working properly using 'minicom'.  (I also have now tested
> with 2.6.37-rc5 with the same result.)  Characters appear to be
> getting lost/dropped in the communication... for example, I *expect*
> the following on the minicom terminal screen when I start it up as
> it initializes the modem:
> 
> -------------------
> AT S7=45 S0=0 L1 V1 X4 &c1 E1 Q0
> OK
> 
> -------------------
> 
> The blinking cursor will be on the line following the OK.  This is
> what happens when using kernel 2.6.35.  However, when I use
> 2.6.37-rc5 this is what I see:
> 
> -------------------
> AT S7=45 S0=0 L1
> -------------------
> 
> Sometimes there is a character or two more on the screen but there
> will be no OK and the cursor will be blinking at the end of the line
> of commands... which leads me to believe that the modem did not see
> the CR+LF from the application.  If I simply press enter on the
> terminal, then I'll see the OK as expected.  So it seems to me that
> only the first bunch of characters are making it through and that
> the rest are getting dropped for some reason.
> 
> setserial tells me the following about the port:
> 
> # setserial -G /dev/ttyS4
> /dev/ttyS4 uart 16950/954 port 0x0000 irq 18 baud_base 4000000
> spd_normal skip_test
> 
> I think I can say with confidence that the problem started with 2.6.36.
> 
> What can I do to help solve the problem?

What type of device is this?  A pci card or something else?  What driver
controls it?

Also, the best thing to do would be if you could run 'git bisect' to
narrow the problem down to the specific patch that caused the problem.
Any chance you could do that?

thanks,

greg k-h

RE: Mainpine IQ Express Rev3 problems beginning 2.6.36

[Lee Howard]

> From: Greg KH [mailto:greg@kroah.com] 
> Sent: Wednesday, December 08, 2010 10:43 PM
> 
> On Wed, Dec 08, 2010 at 03:55:29PM -0800, Lee Howard wrote:
> > Hello everyone,
> > 
> > A week ago I had a customer report to me that they were having 
> > problems using the Mainpine IQ Express Rev3 (multiport modem which 
> > uses the Oxsemi OXPCIe95x chipset) after updating their system from 
> > kernel 2.6.22.10 (which they patched because native support 
> for the IQ 
> > Express didn't enter the kernel until 2.6.28) to kernel 2.6.36.
> > 
> > As I had never used any 2.6.36 kernel, myself, I explained 
> that I had 
> > experienced no problem with the 2.6.35.6 kernel (as found in Fedora 
> > 14) at which point they installed kernel 2.6.35.8 and reported back 
> > that this had resolved the problem for them.
> > 
> > Following their report I then tested by installing the 2.6.37-rc4 
> > kernel (using 'make oldconfig', taking .config from the Fedora 14 
> > kernel that was working), and I was quickly able to determine that 
> > there were problems because simple communications with the 
> modems were 
> > not working properly using 'minicom'.  (I also have now tested with 
> > 2.6.37-rc5 with the same result.)  Characters appear to be getting 
> > lost/dropped in the communication... for example, I *expect* the 
> > following on the minicom terminal screen when I start it up as it 
> > initializes the modem:
> > 
> > -------------------
> > AT S7=45 S0=0 L1 V1 X4 &c1 E1 Q0
> > OK
> > 
> > -------------------
> > 
> > The blinking cursor will be on the line following the OK.  This is 
> > what happens when using kernel 2.6.35.  However, when I use
> > 2.6.37-rc5 this is what I see:
> > 
> > -------------------
> > AT S7=45 S0=0 L1
> > -------------------
> > 
> > Sometimes there is a character or two more on the screen but there 
> > will be no OK and the cursor will be blinking at the end of 
> the line 
> > of commands... which leads me to believe that the modem did not see 
> > the CR+LF from the application.  If I simply press enter on the 
> > terminal, then I'll see the OK as expected.  So it seems to me that 
> > only the first bunch of characters are making it through 
> and that the 
> > rest are getting dropped for some reason.
> > 
> > setserial tells me the following about the port:
> > 
> > # setserial -G /dev/ttyS4
> > /dev/ttyS4 uart 16950/954 port 0x0000 irq 18 baud_base 4000000 
> > spd_normal skip_test
> > 
> > I think I can say with confidence that the problem started 
> with 2.6.36.
> > 
> > What can I do to help solve the problem?
> 
> What type of device is this?  A pci card or something else?

The Mainpine IQ Express cards are multiport PCIe cards with modems attached
to the serial ports.

> What driver controls it?

8250

> Also, the best thing to do would be if you could run 'git 
> bisect' to narrow the problem down to the specific patch that 
> caused the problem.
> Any chance you could do that?

I've been at that for three days now.  It's very tedious and cumbersome
because, even starting with 'git bisect start -- drivers/serial' which
narrows-down the anticipated number of runs to 6, it's very difficult to do
because most of the kernel revisions that are being tested have some bug in
them (they don't build at all, they have oopses, etc.) and I find myself
spending a lot of time only to have to do a 'git bisect skip' if I don't
want to try to work-around those problems.  Eventually I found myself simply
disabling modules in the build that I don't need to perform the test... And
that worked better until I started running into other problems in the test
that were not the same as the one I was having before... So when I'm doing
'git bisect' and come across a revision that doesn't work but doesn't have
the same problems as the target problem, what do I do?  Should I mark it
"bad" or "skip" it?

Thanks,

Lee.

Re: Mainpine IQ Express Rev3 problems beginning 2.6.36

[Greg KH]

On Sat, Dec 11, 2010 at 04:36:07PM -0800, Lee Howard wrote:
> > What type of device is this?  A pci card or something else?
> 
> The Mainpine IQ Express cards are multiport PCIe cards with modems attached
> to the serial ports.
> 
> > What driver controls it?
> 
> 8250
> 
> > Also, the best thing to do would be if you could run 'git 
> > bisect' to narrow the problem down to the specific patch that 
> > caused the problem.
> > Any chance you could do that?
> 
> I've been at that for three days now.  It's very tedious and cumbersome
> because, even starting with 'git bisect start -- drivers/serial' which
> narrows-down the anticipated number of runs to 6, it's very difficult to do
> because most of the kernel revisions that are being tested have some bug in
> them (they don't build at all, they have oopses, etc.) and I find myself
> spending a lot of time only to have to do a 'git bisect skip' if I don't
> want to try to work-around those problems.  Eventually I found myself simply
> disabling modules in the build that I don't need to perform the test... And
> that worked better until I started running into other problems in the test
> that were not the same as the one I was having before... So when I'm doing
> 'git bisect' and come across a revision that doesn't work but doesn't have
> the same problems as the target problem, what do I do?  Should I mark it
> "bad" or "skip" it?

Don't limit yourself to changes in drivers/serial as there are lots of
tty fixes in other parts of the kernel that could have caused issues
with this.

As for build issues, try to make a minimal working config for your
system, using 'make localmodconfig'.  That will speed up your build time
immensely as well as reduce your chances of build and runtime problems
with the intermediate kernels.

best of luck,

greg k-h

RE: Mainpine IQ Express Rev3 problems beginning 2.6.36

[Lee Howard]

> -----Original Message-----
> From: Greg KH [mailto:greg@kroah.com] 
> Sent: Sunday, December 12, 2010 8:52 AM

> As for build issues, try to make a minimal working config for 
> your system, using 'make localmodconfig'.  That will speed up 
> your build time immensely as well as reduce your chances of 
> build and runtime problems with the intermediate kernels.

Thank-you, that did help immensely.

Here's the 'git bisect' result...

--------------
7a56aa45982bb87bfca98a2832b5ae782c03364a is the first bad commit 
commit 7a56aa45982bb87bfca98a2832b5ae782c03364a
Author: Yegor Yefremov <yegor_sub1@visionsystems.de>
Date:   Wed Jun 16 16:29:55 2010 +0200

    serial: add UART_CAP_EFR and UART_CAP_SLEEP flags to 16C950 UARTs
definition
    
    Adding UART_CAP_EFR and UART_CAP_SLEEP flags will enable sleep mode
    and automatic CTS flow control for 16C950 UARTs. It will also avoid
    capabilities detection warning like this:
    
    "ttyS0: detected caps 00000700 should be 00000100"
    
    Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

:040000 040000 1776ca8d5c653834363c0778b5b404ee52bd2d69
b81cfe4f302a674935181bd248641873820517e5 M      drivers
--------------

Indeed, if I remove the UART_CAP_EFR flag from later kernel revisions there
is no problem.

Here is the 'dmesg' output for 8250 after removing UART_CAP_EFR...

--------------
[    0.980209] Serial: 8250/16550 driver, 32 ports, IRQ sharing enabled
[    1.245280] serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
[    1.266813] 00:09: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
[    1.266936] serial 0000:02:00.0: PCI INT A -> GSI 18 (level, low) -> IRQ
18
[    1.266954] 1 ports detected on Oxford PCI Express device
[    1.267029] ttyS4: detected caps 00000700 should be 00000500
[    1.267043] 0000:02:00.0: ttyS4 at MMIO 0xfd5fd000 (irq = 18) is a
16C950/954
[    1.267095] serial 0000:03:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ
16
[    1.267105] 4 ports detected on Oxford PCI Express device
[    1.267175] ttyS5: detected caps 00000700 should be 00000500
[    1.267180] 0000:03:00.0: ttyS5 at MMIO 0xfc9fd000 (irq = 16) is a
16C950/954
[    1.267269] ttyS6: detected caps 00000700 should be 00000500
[    1.267274] 0000:03:00.0: ttyS6 at MMIO 0xfc9fd200 (irq = 16) is a
16C950/954
[    1.267362] ttyS7: detected caps 00000700 should be 00000500
[    1.267366] 0000:03:00.0: ttyS7 at MMIO 0xfc9fd400 (irq = 16) is a
16C950/954
[    1.267454] ttyS8: detected caps 00000700 should be 00000500
[    1.267459] 0000:03:00.0: ttyS8 at MMIO 0xfc9fd600 (irq = 16) is a
16C950/954
[    1.267505] serial 0000:04:00.0: PCI INT A -> GSI 18 (level, low) -> IRQ
18
[    1.267514] 2 ports detected on Oxford PCI Express device
[    1.267583] ttyS9: detected caps 00000700 should be 00000500
[    1.267588] 0000:04:00.0: ttyS9 at MMIO 0xfcffd000 (irq = 18) is a
16C950/954
[    1.267678] ttyS10: detected caps 00000700 should be 00000500
[    1.267683] 0000:04:00.0: ttyS10 at MMIO 0xfcffd200 (irq = 18) is a
16C950/954
[    1.267723] serial 0000:06:00.0: PCI INT A -> GSI 19 (level, low) -> IRQ
19
[    1.288452] 0000:06:00.0: ttyS11 at I/O 0xcf00 (irq = 19) is a 16550A
[    1.309208] 0000:06:00.0: ttyS12 at I/O 0xcf08 (irq = 19) is a 16550A
[    1.329963] 0000:06:00.0: ttyS13 at I/O 0xcf10 (irq = 19) is a 16550A
[    1.350723] 0000:06:00.0: ttyS14 at I/O 0xcf18 (irq = 19) is a 16550A
--------------

00:09 is the on-board serial controller, so that's ttyS1

0000:02:00.0 is a 1-port Rev3 IQ Express, that's ttyS4

0000:03:00.0 is a 4-port Rev3 IQ Express, that's ttyS5-ttyS8

0000:04:00.0 is a 2-port Rev3 IQ Express, that's ttyS9-ttyS10

0000:06:00.0 is a 4-port Rev2 IQ Express, that's ttyS11-ttyS14  (these had
no problem).

Thanks,

Lee.

RE: Mainpine IQ Express Rev3 problems beginning 2.6.36

[Lee Howard]

> -----Original Message-----
> From: linux-serial-owner@vger.kernel.org 
> [mailto:linux-serial-owner@vger.kernel.org] On Behalf Of Lee Howard
> Sent: Tuesday, December 14, 2010 11:50 AM
> To: 'Greg KH'
> Cc: linux-serial@vger.kernel.org
> Subject: RE: Mainpine IQ Express Rev3 problems beginning 2.6.36
> 
> > -----Original Message-----
> > From: Greg KH [mailto:greg@kroah.com]
> > Sent: Sunday, December 12, 2010 8:52 AM
> 
> > As for build issues, try to make a minimal working config for your 
> > system, using 'make localmodconfig'.  That will speed up your build 
> > time immensely as well as reduce your chances of build and runtime 
> > problems with the intermediate kernels.
> 
> Thank-you, that did help immensely.
> 
> Here's the 'git bisect' result...
> 
> --------------
> 7a56aa45982bb87bfca98a2832b5ae782c03364a is the first bad 
> commit commit 7a56aa45982bb87bfca98a2832b5ae782c03364a
> Author: Yegor Yefremov <yegor_sub1@visionsystems.de>
> Date:   Wed Jun 16 16:29:55 2010 +0200
> 
>     serial: add UART_CAP_EFR and UART_CAP_SLEEP flags to 
> 16C950 UARTs definition
>     
>     Adding UART_CAP_EFR and UART_CAP_SLEEP flags will enable 
> sleep mode
>     and automatic CTS flow control for 16C950 UARTs. It will 
> also avoid
>     capabilities detection warning like this:
>     
>     "ttyS0: detected caps 00000700 should be 00000100"
>     
>     Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
>     Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> 
> :040000 040000 1776ca8d5c653834363c0778b5b404ee52bd2d69
> b81cfe4f302a674935181bd248641873820517e5 M      drivers
> --------------
> 
> Indeed, if I remove the UART_CAP_EFR flag from later kernel 
> revisions there is no problem.

Greg,

What's to be done?

Thanks,

Lee.

Re: Mainpine IQ Express Rev3 problems beginning 2.6.36

[Greg KH]

On Fri, Dec 17, 2010 at 05:25:19AM -0800, Lee Howard wrote:
> > -----Original Message-----
> > From: linux-serial-owner@vger.kernel.org 
> > [mailto:linux-serial-owner@vger.kernel.org] On Behalf Of Lee Howard
> > Sent: Tuesday, December 14, 2010 11:50 AM
> > To: 'Greg KH'
> > Cc: linux-serial@vger.kernel.org
> > Subject: RE: Mainpine IQ Express Rev3 problems beginning 2.6.36
> > 
> > > -----Original Message-----
> > > From: Greg KH [mailto:greg@kroah.com]
> > > Sent: Sunday, December 12, 2010 8:52 AM
> > 
> > > As for build issues, try to make a minimal working config for your 
> > > system, using 'make localmodconfig'.  That will speed up your build 
> > > time immensely as well as reduce your chances of build and runtime 
> > > problems with the intermediate kernels.
> > 
> > Thank-you, that did help immensely.
> > 
> > Here's the 'git bisect' result...
> > 
> > --------------
> > 7a56aa45982bb87bfca98a2832b5ae782c03364a is the first bad 
> > commit commit 7a56aa45982bb87bfca98a2832b5ae782c03364a
> > Author: Yegor Yefremov <yegor_sub1@visionsystems.de>
> > Date:   Wed Jun 16 16:29:55 2010 +0200
> > 
> >     serial: add UART_CAP_EFR and UART_CAP_SLEEP flags to 
> > 16C950 UARTs definition
> >     
> >     Adding UART_CAP_EFR and UART_CAP_SLEEP flags will enable 
> > sleep mode
> >     and automatic CTS flow control for 16C950 UARTs. It will 
> > also avoid
> >     capabilities detection warning like this:
> >     
> >     "ttyS0: detected caps 00000700 should be 00000100"
> >     
> >     Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
> >     Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> > 
> > :040000 040000 1776ca8d5c653834363c0778b5b404ee52bd2d69
> > b81cfe4f302a674935181bd248641873820517e5 M      drivers
> > --------------
> > 
> > Indeed, if I remove the UART_CAP_EFR flag from later kernel 
> > revisions there is no problem.
> 
> Greg,
> 
> What's to be done?

Sorry for the delay, I think Pavel's posted patch will solve this issue
for you, right?

thanks,

greg k-h

RE: Mainpine IQ Express Rev3 problems beginning 2.6.36

[Lee Howard]

> -----Original Message-----
> From: Greg KH [mailto:greg@kroah.com] 
> Sent: Monday, January 10, 2011 4:03 PM
> To: Lee Howard
> Cc: linux-serial@vger.kernel.org
> Subject: Re: Mainpine IQ Express Rev3 problems beginning 2.6.36
> 
> On Fri, Dec 17, 2010 at 05:25:19AM -0800, Lee Howard wrote:
> > > -----Original Message-----
> > > From: linux-serial-owner@vger.kernel.org
> > > [mailto:linux-serial-owner@vger.kernel.org] On Behalf Of 
> Lee Howard
> > > Sent: Tuesday, December 14, 2010 11:50 AM
> > > To: 'Greg KH'
> > > Cc: linux-serial@vger.kernel.org
> > > Subject: RE: Mainpine IQ Express Rev3 problems beginning 2.6.36
> > > 
> > > > -----Original Message-----
> > > > From: Greg KH [mailto:greg@kroah.com]
> > > > Sent: Sunday, December 12, 2010 8:52 AM
> > > 
> > > > As for build issues, try to make a minimal working 
> config for your 
> > > > system, using 'make localmodconfig'.  That will speed up your 
> > > > build time immensely as well as reduce your chances of 
> build and 
> > > > runtime problems with the intermediate kernels.
> > > 
> > > Thank-you, that did help immensely.
> > > 
> > > Here's the 'git bisect' result...
> > > 
> > > --------------
> > > 7a56aa45982bb87bfca98a2832b5ae782c03364a is the first bad commit 
> > > commit 7a56aa45982bb87bfca98a2832b5ae782c03364a
> > > Author: Yegor Yefremov <yegor_sub1@visionsystems.de>
> > > Date:   Wed Jun 16 16:29:55 2010 +0200
> > > 
> > >     serial: add UART_CAP_EFR and UART_CAP_SLEEP flags to 16C950 
> > > UARTs definition
> > >     
> > >     Adding UART_CAP_EFR and UART_CAP_SLEEP flags will 
> enable sleep 
> > > mode
> > >     and automatic CTS flow control for 16C950 UARTs. It will also 
> > > avoid
> > >     capabilities detection warning like this:
> > >     
> > >     "ttyS0: detected caps 00000700 should be 00000100"
> > >     
> > >     Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
> > >     Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> > > 
> > > :040000 040000 1776ca8d5c653834363c0778b5b404ee52bd2d69
> > > b81cfe4f302a674935181bd248641873820517e5 M      drivers
> > > --------------
> > > 
> > > Indeed, if I remove the UART_CAP_EFR flag from later kernel 
> > > revisions there is no problem.
> > 
> > Greg,
> > 
> > What's to be done?
> 
> Sorry for the delay, I think Pavel's posted patch will solve 
> this issue for you, right?

I've looked in the linux-serial archives for posts by Pavel for the last
month, but I don't see a patch.  Please tell me where I can find this patch.

Thanks,

Lee.

Re: Mainpine IQ Express Rev3 problems beginning 2.6.36

[Greg KH]

[-- Attachment #1: Type: text/plain, Size: 2756 bytes --]

On Tue, Jan 11, 2011 at 11:16:06AM -0800, Lee Howard wrote:
> 
> > -----Original Message-----
> > From: Greg KH [mailto:greg@kroah.com] 
> > Sent: Monday, January 10, 2011 4:03 PM
> > To: Lee Howard
> > Cc: linux-serial@vger.kernel.org
> > Subject: Re: Mainpine IQ Express Rev3 problems beginning 2.6.36
> > 
> > On Fri, Dec 17, 2010 at 05:25:19AM -0800, Lee Howard wrote:
> > > > -----Original Message-----
> > > > From: linux-serial-owner@vger.kernel.org
> > > > [mailto:linux-serial-owner@vger.kernel.org] On Behalf Of 
> > Lee Howard
> > > > Sent: Tuesday, December 14, 2010 11:50 AM
> > > > To: 'Greg KH'
> > > > Cc: linux-serial@vger.kernel.org
> > > > Subject: RE: Mainpine IQ Express Rev3 problems beginning 2.6.36
> > > > 
> > > > > -----Original Message-----
> > > > > From: Greg KH [mailto:greg@kroah.com]
> > > > > Sent: Sunday, December 12, 2010 8:52 AM
> > > > 
> > > > > As for build issues, try to make a minimal working 
> > config for your 
> > > > > system, using 'make localmodconfig'.  That will speed up your 
> > > > > build time immensely as well as reduce your chances of 
> > build and 
> > > > > runtime problems with the intermediate kernels.
> > > > 
> > > > Thank-you, that did help immensely.
> > > > 
> > > > Here's the 'git bisect' result...
> > > > 
> > > > --------------
> > > > 7a56aa45982bb87bfca98a2832b5ae782c03364a is the first bad commit 
> > > > commit 7a56aa45982bb87bfca98a2832b5ae782c03364a
> > > > Author: Yegor Yefremov <yegor_sub1@visionsystems.de>
> > > > Date:   Wed Jun 16 16:29:55 2010 +0200
> > > > 
> > > >     serial: add UART_CAP_EFR and UART_CAP_SLEEP flags to 16C950 
> > > > UARTs definition
> > > >     
> > > >     Adding UART_CAP_EFR and UART_CAP_SLEEP flags will 
> > enable sleep 
> > > > mode
> > > >     and automatic CTS flow control for 16C950 UARTs. It will also 
> > > > avoid
> > > >     capabilities detection warning like this:
> > > >     
> > > >     "ttyS0: detected caps 00000700 should be 00000100"
> > > >     
> > > >     Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
> > > >     Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> > > > 
> > > > :040000 040000 1776ca8d5c653834363c0778b5b404ee52bd2d69
> > > > b81cfe4f302a674935181bd248641873820517e5 M      drivers
> > > > --------------
> > > > 
> > > > Indeed, if I remove the UART_CAP_EFR flag from later kernel 
> > > > revisions there is no problem.
> > > 
> > > Greg,
> > > 
> > > What's to be done?
> > 
> > Sorry for the delay, I think Pavel's posted patch will solve 
> > this issue for you, right?
> 
> I've looked in the linux-serial archives for posts by Pavel for the last
> month, but I don't see a patch.  Please tell me where I can find this patch.

I've attached it below.

thanks,

greg k-h

[-- Attachment #2: p --]
[-- Type: text/x-pascal, Size: 3726 bytes --]

>From pavel@ucw.cz Sat Jan  8 23:38:58 2011
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Date: Sun, 9 Jan 2011 08:38:48 +0100
From: Pavel Machek <pavel@ucw.cz>
To: Greg KH <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	linux-kernel@vger.kernel.org, stable@kernel.org,
	stable-review@kernel.org, torvalds@linux-foundation.org,
	akpm@linux-foundation.org
Subject: unbreak billionton CF card (was Re: [000/152] 2.6.36.3-stable
 review)
Message-ID: <20110109073848.GA1553@ucw.cz>
References: <20110106002500.GA3172@kroah.com>
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Unbreak Billionton CF bluetooth card. This actually fixes a regression
on zaurus.

Signed-off-by: Pavel Machek <pavel@ucw.cz>

---

> > Flow control flag seems to be responsible.
> > 
> > But... it hits me and then... me. So I'd like to see it resolved in
> > devel tree, but it may not 100% vital for stable.
> 
> Ok, care to make up a patch I can apply for Linus's tree first that
> works for you?

./drivers/serial - ./drivers/serial.ofic
diff -X /usr/src/linux/.gitignore -ur ./drivers/serial.ofic/8250.c ./drivers/serial/8250.c
--- ./drivers/serial.ofic/8250.c	2011-01-02 21:25:29.000000000 +0100
+++ ./drivers/serial/8250.c	2011-01-09 08:10:39.000000000 +0100
@@ -236,7 +236,8 @@
 		.fifo_size	= 128,
 		.tx_loadsz	= 128,
 		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-		.flags		= UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
+		/* UART_CAP_EFR breaks billionon CF bluetooth card. */
+		.flags		= UART_CAP_FIFO | UART_CAP_SLEEP,
 	},
 	[PORT_16654] = {
 		.name		= "ST16654",

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

RE: Mainpine IQ Express Rev3 problems beginning 2.6.36

[Lee Howard]

> -----Original Message-----
> From: Greg KH [mailto:greg@kroah.com] 
> Sent: Tuesday, January 11, 2011 3:03 PM
> To: Lee Howard
> Cc: linux-serial@vger.kernel.org
> Subject: Re: Mainpine IQ Express Rev3 problems beginning 2.6.36
> 
> On Tue, Jan 11, 2011 at 11:16:06AM -0800, Lee Howard wrote:
> > 
> > > -----Original Message-----
> > > From: Greg KH [mailto:greg@kroah.com]
> > > Sent: Monday, January 10, 2011 4:03 PM
> > > To: Lee Howard
> > > Cc: linux-serial@vger.kernel.org
> > > Subject: Re: Mainpine IQ Express Rev3 problems beginning 2.6.36
> > > 
> > > On Fri, Dec 17, 2010 at 05:25:19AM -0800, Lee Howard wrote:
> > > > > -----Original Message-----
> > > > > From: linux-serial-owner@vger.kernel.org
> > > > > [mailto:linux-serial-owner@vger.kernel.org] On Behalf Of
> > > Lee Howard
> > > > > Sent: Tuesday, December 14, 2010 11:50 AM
> > > > > To: 'Greg KH'
> > > > > Cc: linux-serial@vger.kernel.org
> > > > > Subject: RE: Mainpine IQ Express Rev3 problems 
> beginning 2.6.36
> > > > > 
> > > > > > -----Original Message-----
> > > > > > From: Greg KH [mailto:greg@kroah.com]
> > > > > > Sent: Sunday, December 12, 2010 8:52 AM
> > > > > 
> > > > > > As for build issues, try to make a minimal working
> > > config for your
> > > > > > system, using 'make localmodconfig'.  That will 
> speed up your 
> > > > > > build time immensely as well as reduce your chances of
> > > build and
> > > > > > runtime problems with the intermediate kernels.
> > > > > 
> > > > > Thank-you, that did help immensely.
> > > > > 
> > > > > Here's the 'git bisect' result...
> > > > > 
> > > > > --------------
> > > > > 7a56aa45982bb87bfca98a2832b5ae782c03364a is the first 
> bad commit 
> > > > > commit 7a56aa45982bb87bfca98a2832b5ae782c03364a
> > > > > Author: Yegor Yefremov <yegor_sub1@visionsystems.de>
> > > > > Date:   Wed Jun 16 16:29:55 2010 +0200
> > > > > 
> > > > >     serial: add UART_CAP_EFR and UART_CAP_SLEEP flags 
> to 16C950 
> > > > > UARTs definition
> > > > >     
> > > > >     Adding UART_CAP_EFR and UART_CAP_SLEEP flags will
> > > enable sleep
> > > > > mode
> > > > >     and automatic CTS flow control for 16C950 UARTs. It will 
> > > > > also avoid
> > > > >     capabilities detection warning like this:
> > > > >     
> > > > >     "ttyS0: detected caps 00000700 should be 00000100"
> > > > >     
> > > > >     Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
> > > > >     Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> > > > > 
> > > > > :040000 040000 1776ca8d5c653834363c0778b5b404ee52bd2d69
> > > > > b81cfe4f302a674935181bd248641873820517e5 M      drivers
> > > > > --------------
> > > > > 
> > > > > Indeed, if I remove the UART_CAP_EFR flag from later kernel 
> > > > > revisions there is no problem.
> > > > 
> > > > Greg,
> > > > 
> > > > What's to be done?
> > > 
> > > Sorry for the delay, I think Pavel's posted patch will solve this 
> > > issue for you, right?
> > 
> > I've looked in the linux-serial archives for posts by Pavel for the 
> > last month, but I don't see a patch.  Please tell me where 
> I can find this patch.
> 
> I've attached it below.

Thank you.  Sorry for my delay in responding.  Yes, the posted patch will
solve the issue for me.

I was going to look into whether UART_CAP_SLEEP was meaningful without
UART_CAP_EFR because I thought I had read somewhere that it was not.  But I
just haven't managed to make time to do that.

Thanks,

Lee.