Re: [PATCH] pch_dma: Fix channel locking

[Alexander Stein <alexander.stein@systec-electronic.com>]

On Tuesday 28 June 2011 12:34:34 Tomoya MORINAGA wrote:
> (2011/06/27 23:22), Alexander Stein wrote:
> > Ok. I have a 2.6.39 kernel with the following patches:
> > pch_phub: Don't panic if dmi_get_system_info returns NULL
> > drivers/tty/serial/pch_uart.c: don't oops if dmi_get_system_info returns
> > NULL pch_uart: Add console support
> > 
> > I need these to get a booting board with console support on pch_uart.
> > After boot (dma and pch_uart compiled into kernel), I do
> > * setserial /dev/ttyPCH0 ^low_latency
> > * ./raise_dma_fault
> > <- Here I get the message
> 
> Thank you for your information.
> I could see the kernel message.
> However using your patch, it seems the message remains to be seen.
> 
> [  142.401597] pch_uart 0000:02:0a.1: PCH UART : Use DMA Mode
> [  148.011410]
> [  148.011415] =================================
> [  148.011428] [ INFO: inconsistent lock state ]
> [  148.011439] 2.6.39.2+ #5
> [  148.011446] ---------------------------------
> [  148.011455] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
> [  148.011467] gnome-terminal/1759 [HC1[1]:SC0[0]:HE0:SE1] takes:
> [  148.011477]  (&(&pd_chan->lock)->rlock){?.....}, at: [<c0710cc5>]
> pd_prep_slave_sg+0x92/0x26d
> [  148.011509] {HARDIRQ-ON-W} state was registered at:
> [  148.011516]   [<c04618a1>] __lock_acquire+0x2d9/0xbcc
> [  148.011533]   [<c0462594>] lock_acquire+0x94/0xb7
> [  148.011546]   [<c07cec85>] _raw_spin_lock_bh+0x25/0x34
> [  148.011561]   [<c07110d0>] pd_alloc_chan_resources+0xb2/0x165

Are you sure you applied the patch? There shouldn't be a _raw_spin_lock_bh 
here.

Regards,
Alexander