acpi breaks async interface

acpi breaks async interface

[Juraj Bednar]

Hello,


 I just found a strange thing in 2.4.1 (don't know, if the same
occured in 2.4.0) and 2.4.1-ac3. When I enable ACPI, my serial
port starts to drop some characters. When making ppp over this
and doing ping, it causes great packet losts. If I turn ACPI in
this configuration off, it works with no problems. I tried to
switch serial port IRQ to other one (was 4, switched to 3 and
tested) and it didn't help. Maybe something's broken.

 ACPI related boot messages:

Feb  4 23:21:58 idoru kernel: ACPI: Core Subsystem version [20010125]
Feb  4 23:21:58 idoru kernel: ACPI: Subsystem enabled
Feb  4 23:21:58 idoru kernel: ACPI: System firmware supports: C2 C3
Feb  4 23:21:58 idoru kernel: ACPI: System firmware supports: S0 S1 S4 S5

[root@idoru log]# cat /proc/interrupts 
           CPU0       
  0:      57278          XT-PIC  timer
  1:       2658          XT-PIC  keyboard
  2:          0          XT-PIC  cascade
  4:      49530          XT-PIC  serial
  5:          1          XT-PIC  soundblaster
 10:         15          XT-PIC  aha152x
 11:         60          XT-PIC  eth0
 12:      27772          XT-PIC  PS/2 Mouse
 14:     213118          XT-PIC  ide0
 15:       3298          XT-PIC  ide1
NMI:          0 
LOC:          0 
ERR:          0





           Have a nice day,
                  Juraj.

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Re: acpi breaks async interface

[Pavel Machek]

Hi!

>  I just found a strange thing in 2.4.1 (don't know, if the same
> occured in 2.4.0) and 2.4.1-ac3. When I enable ACPI, my serial
> port starts to drop some characters. When making ppp over this
> and doing ping, it causes great packet losts. If I turn ACPI in
> this configuration off, it works with no problems. I tried to
> switch serial port IRQ to other one (was 4, switched to 3 and
> tested) and it didn't help. Maybe something's broken.
> 
>  ACPI related boot messages:
> 
> Feb  4 23:21:58 idoru kernel: ACPI: Core Subsystem version [20010125]
> Feb  4 23:21:58 idoru kernel: ACPI: Subsystem enabled
> Feb  4 23:21:58 idoru kernel: ACPI: System firmware supports: C2 C3
> Feb  4 23:21:58 idoru kernel: ACPI: System firmware supports: S0 S1 S4 S5
> 
> [root@idoru log]# cat /proc/interrupts 
>            CPU0       
>   0:      57278          XT-PIC  timer
>   1:       2658          XT-PIC  keyboard
>   2:          0          XT-PIC  cascade
>   4:      49530          XT-PIC  serial
>   5:          1          XT-PIC  soundblaster
>  10:         15          XT-PIC  aha152x
>  11:         60          XT-PIC  eth0
>  12:      27772          XT-PIC  PS/2 Mouse
>  14:     213118          XT-PIC  ide0
>  15:       3298          XT-PIC  ide1
> NMI:          0 
> LOC:          0 
> ERR:          0

ACPI slows down CPU quite a lot. Maybe cpu is so slow it can no longer
handle serial in time?

Try running 

while(1);

program while doing serial transfers.
								Pavel
-- 
I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care."
Panos Katsaloulis describing me w.r.t. patents at discuss@linmodems.org
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