On 08/16/11 10:06, Sankara Muthukrishnan wrote:

Hello everyone,

First of all, thanks to everyone for the RT patch and it is awesome
work. I got stable 3.0.1 + 3.0.1-rt8 patch single-core kernel working
on a PandaBoard (with another patch for getting the high resolution
timer to work on PandaBoard). With cyclictest, I am seeing a maximum
latency of ~25 us (~36 us with some ethernet traffic). The test
results are really really promising and kudos to tglx, et al. I am
also planning to run the tests for a longer period of time.

However, with the RT patch applied, I cannot get the SMP kernel to
boot [Note: stable 3.0.1 SMP kernel boots just fine without RT patch].
I have tried with and without the other high-resolution timer patch.
It hangs the same way very early with the following message:
*************
reading uImage

2828444 bytes read
Booting from mmc0 ...
## Booting kernel from Legacy Image at 82000000 ...
   Image Name:   Linux-3.0.1-rt8+
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    2828380 Bytes = 2.7 MiB
   Load Address: 80008000
   Entry Point:  80008000
   Verifying Checksum ... OK
   Loading Kernel Image ... OK
OK

Starting kernel ...

Uncompressing Linux... done, booting the kernel.
*************

I have attached 4 kernel config files - 2 booting fine and 2 not
booting (Legend for interpreting file names: sc = single core, rt =
rt-patch, hrt = high-resolution-timer-patch)

Note: I have tried even earlier version of the RT patches and all of
them fail. However, I vaguely recall the first or second RT patch that
was released booted SMP fine but I cannot make it work again now.

Has anyone been successful in booting SMP on panda board or other
OMAP4/ARM targets with RT patch?

Is there anything wrong with my config files for SMP with RT patch on ARM?

Any suggestions to debug early hangs on panda board with RT patch ?

Thanks in advance,
Sankara Muthukrishnan

SMP Panda is booting fine for me on a slightly older version: 3.0.0-rt6

gcc 4.3.3

Config is attached.

I used make omap2plus_defconfig then tweaked a few items:

# this allows USB thumb drive
# Device Drivers -> USB support -> EHCI HCD (USB 2.0) support
CONFIG_USB_EHCI_HCD=y
# Device Drivers -> USB support -> EHCI support for OMAP3 and later chips
CONFIG_USB_EHCI_HCD_OMAP=y

# ethernet device
# Device Drivers -> Network device support -> USB Network Adapters ->
#  Multi-purpose USB Networking Framework ->
#  SMSC LAN95XX based USB 2.0 10/100 ethernet devices
CONFIG_USB_NET_SMSC95XX=y

# Kernel Features -> Preemption Model -> Fully Preemptible Kernel (RT)


-Frank