Re: [PATCH RT 2/2] fix printk flush of messages

[Frank Rowand]

added recipients...

On 08/21/12 07:30, Michael Thalmeier wrote:
> Frank Rowand <frank.rowand <at> am.sony.com> writes:
> 
>>
>>
>> Updates console-make-rt-friendly.patch
>>
>> #ifdef CONFIG_PREEMPT_RT_FULL, printk() output is never flushed by
>> printk() because:
>> ...
>>
>> On system boot some printk() output is flushed because register_console()
>> and tty_open() call console_unlock().
>>
>> This change also fixes the problem that was previously fixed by
>> preempt-rt-allow-immediate-magic-sysrq-output-for-preempt_rt_full.patch
>>
>> Signed-off-by: Frank Rowand <frank.rowand <at> am.sony.com>
>>
>> ---
>>  kernel/printk.c |    2 	1 +	1 -	0 !
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> Index: b/kernel/printk.c
>> ===================================================================
>> --- a/kernel/printk.c
>> +++ b/kernel/printk.c
>> @@ -847,7 +847,7 @@ static int console_trylock_for_printk(un
>>  	int retval = 0, wake = 0;
>>  #ifdef CONFIG_PREEMPT_RT_FULL
>>  	int lock = !early_boot_irqs_disabled && !irqs_disabled_flags(flags) &&
>> -		!preempt_count();
>> +		(preempt_count() <= 1);
>>  #else
>>  	int lock = 1;
>>  #endif
>>
>>
> 
> I have seen that this patch is applied in the 3.4 stable rt series.
> As we are using the 3.0 stable rt kernel I have tested this patch on this
> kernel series (on a Freescale i.MX31 based board) and have not found any
> problems so far.
> Is there something I have missed why this patch has not found its way
> in the 3.0 series ?
> 
> Thanks in advance,
> Michael

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