[linux-yocto] [linux-yocto-rt][PATCH] printk: revert part of code of printk emergency mechanism

[Hongzhi, Song]

On 4/24/19 4:04 AM, Bruce Ashfield wrote:
> Since this is still being discussed on the -rt mailing list, I'm going 
> to wait to see how that shakes out before merging the change.


Yes, but it seems like that upstream won't fix the issue in a short time.

--Hongzhi



>
> Bruce
>
> On Mon, Apr 22, 2019 at 11:20 PM Hongzhi, Song 
> <hongzhi.song at windriver.com <mailto:hongzhi.song at windriver.com>> wrote:
>
>     Please merge to v5.0/standard/preempt-rt/base and
>     v5.0/standard/preempt-rt/intel-x86
>
>
>     --Hongzhi
>
>
>     On 4/23/19 11:14 AM, Hongzhi.Song wrote:
>     > Two commits from rt-kernel cause the following disorder log at the
>     > early stage of boot with qemux86-64. Maybe it has other disorder
>     logs
>     > which I omit.
>     >
>     > Commits:
>     > 7128a815: printk: introduce emergency messages
>     > b9d460e4: serial: 8250: implement write_atomic
>     >
>     > [    0.401166] 000: 6200.04 BogoMIPS (lpj=3100023)
>     > [    0.877953] 000: Intel(R) Core(TM)2 Duo CPU     T7700 @ 2.40GHz
>     > [    0.877953] 000:  (family: 0x6, model: 0xf
>     > [    0.877953] 000: , stepping: 0xb)
>     > [    1.255009] 000:  5
>     > [    1.255167] 000:  *10
>     > [    1.255295] 000:  11
>     > [    1.255406] 000: )
>     >
>     > Obviously, the printk emergency mechanism doesn't work as expected.
>     > Removing partial code of printk emergency mechanism can
>     > fix the issue temporarily.
>     >
>     > Signed-off-by: Hongzhi.Song <hongzhi.song at windriver.com
>     <mailto:hongzhi.song at windriver.com>>
>     > ---
>     >   kernel/printk/printk.c | 4 ++++
>     >   1 file changed, 4 insertions(+)
>     >
>     > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
>     > index 997d07b..99d4a94 100644
>     > --- a/kernel/printk/printk.c
>     > +++ b/kernel/printk/printk.c
>     > @@ -1726,6 +1726,7 @@ static void call_console_drivers(u64 seq,
>     const char *ext_text, size_t ext_len,
>     >                       con->wrote_history = 1;
>     >                       con->printk_seq = seq - 1;
>     >               }
>     > +#if 0
>     >               if (con->write_atomic && level <
>     emergency_console_loglevel &&
>     >                   facility == 0) {
>     >                       /* skip emergency messages, already printed */
>     > @@ -1733,6 +1734,7 @@ static void call_console_drivers(u64 seq,
>     const char *ext_text, size_t ext_len,
>     >                               con->printk_seq = seq;
>     >                       continue;
>     >               }
>     > +#endif
>     >               if (con->flags & CON_BOOT && facility == 0) {
>     >                       /* skip emergency messages, already printed */
>     >                       if (con->printk_seq < seq)
>     > @@ -3134,10 +3136,12 @@ static void
>     call_emergency_console_drivers(int level, const char *text,
>     >       for_each_console(con) {
>     >               if (!(con->flags & CON_ENABLED))
>     >                       continue;
>     > +#if 0
>     >               if (con->write_atomic && level <
>     emergency_console_loglevel) {
>     >                       con->write_atomic(con, text, text_len);
>     >                       continue;
>     >               }
>     > +#endif
>     >               if (con->write && (con->flags & CON_BOOT)) {
>     >                       con->write(con, text, text_len);
>     >                       continue;
>
>
>
> -- 
> - Thou shalt not follow the NULL pointer, for chaos and madness await 
> thee at its end
> - "Use the force Harry" - Gandalf, Star Trek II
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.yoctoproject.org/pipermail/linux-yocto/attachments/20190424/cef217bf/attachment-0001.html>