What are rules for acpi_ex_enter_interpreter?

From: Petr Vandrovec (vandrove@vc.cvut.cz)
Date: Tue Jul 03 2001 - 20:38:07 EST

Hi Andrew,
  ACPI was reporting no S* states on my machine (ASUS A7V) for some time
and today I finally got some time to debug it. Problem is that during
initialization namespace init calls acpi_walk_namespace without
interpreter lock held - but it is wrong - as you can see from stack
trace, acpi_walk_namespace can call down to acpi_ev_address_space_dispatch,
which can call acpi_ex_exit_interpreter - and this is fatal on unlocked
lock :-(

  This points us to another problem - when acpi is compiled into kernel,
for some reason there is pending signal in thread doing ospm_busmgr and
ospm_system initialization, so it fails to acquire lock because of
down_interruptible fails... but does not print any message, just no
valid S states are found. When acpi is compiled as module, modprobe
hangs until you hit ^C - then it is converted to previous case - module
says OK, but did nothing in reality.

  I did NOT verified other callers of acpi_walk_namespace... And there
is still some problem left, as although now S5 is listed as available,
poweroff still does nothing instead of poweroff.
                                        Best regards,
                                                Petr Vandrovec
                                                vandrove@vc.cvut.cz

Jul 4 02:03:02 ppc kernel: CPU: 0
Jul 4 02:03:02 ppc kernel: EIP: 0010:[printstate+9/48]
Jul 4 02:03:02 ppc kernel: EFLAGS: 00000202
Jul 4 02:03:02 ppc kernel: eax: 0000000e ebx: c01680d0 ecx: c020e996 edx: 00000001
Jul 4 02:03:02 ppc kernel: esi: cff75e3c edi: c1428a4c ebp: c1428c8c esp: c140dc34
Jul 4 02:03:02 ppc kernel: ds: 0018 es: 0018 ss: 0018
Jul 4 02:03:02 ppc kernel: Process swapper (pid: 1, stackpage=c140d000)
Jul 4 02:03:02 ppc kernel: Stack: c140dc38 00000018 c016955a c016206c 000fdf00 00000000 00000000 00000000
Jul 4 02:03:02 ppc kernel: c1428a4c c140dcd4 c0166438 c1428a4c 00000001 000fdf00 00000000 00000020
Jul 4 02:03:02 ppc kernel: c140dcd4 c140e50c c020c5cc c015c8a5 c140e50c c020c685 00000001 c020e320
Jul 4 02:03:02 ppc kernel: Call Trace: [acpi_ex_exit_interpreter+26/48] [acpi_ev_address_space_dispatch+124/208] [acpi_ex_read_field_datum+120/224] [debug_print+21/160] [function_status_exit+49/64]
Jul 4 02:03:02 ppc kernel: [acpi_ex_extract_from_field+123/432] [acpi_ex_common_access_field+56/64] [acpi_ex_access_region_field+36/64] [acpi_ex_read_data_from_field+220/288] [acpi_ex_resolve_node_to_value+411/560] [acpi_ex_resolve_to_value+42/80]
Jul 4 02:03:02 ppc kernel: [acpi_ex_resolve_operands+282/768] [acpi_ds_eval_region_operands+56/144] [acpi_ds_exec_end_op+705/752] [acpi_ps_parse_loop+945/1904] [acpi_ut_release_mutex+103/144] [acpi_ut_create_generic_state+63/128]
Jul 4 02:03:02 ppc kernel: [acpi_ps_parse_aml+519/640] [acpi_ds_get_region_arguments+222/256] [acpi_ds_exec_begin_op+0/304] [acpi_ds_exec_end_op+0/752] [acpi_ns_init_one_object+91/96] [acpi_ns_walk_namespace+193/288]
Jul 4 02:03:02 ppc kernel: [acpi_ns_init_one_object+0/96] [acpi_walk_namespace+85/128] [acpi_ns_init_one_object+0/96] [acpi_ns_initialize_objects+61/80] [acpi_ns_init_one_object+0/96] [acpi_enable_subsystem+149/320]
Jul 4 02:03:02 ppc kernel: [acpi_enable_subsystem+188/320] [acpi_init+283/352] [rest_init+0/48] [init+11/320] [rest_init+0/48] [kernel_thread+38/48]
Jul 4 02:03:02 ppc kernel: [init+0/320]
Jul 4 02:03:02 ppc kernel:
Jul 4 02:03:02 ppc kernel: Code: 50 1e 06 50 55 57 56 52 51 53 89 e0 50 e8 b5 fe ff ff 83 c4

diff -urdN linux/drivers/acpi/namespace/nsinit.c linux/drivers/acpi/namespace/nsinit.c
--- linux/drivers/acpi/namespace/nsinit.c Tue Jul 3 15:58:35 2001
+++ linux/drivers/acpi/namespace/nsinit.c Wed Jul 4 02:20:49 2001
@@ -27,6 +27,7 @@
 #include "acpi.h"
 #include "acnamesp.h"
 #include "acdispat.h"
+#include "acinterp.h"
 
 #define _COMPONENT ACPI_NAMESPACE
          MODULE_NAME ("nsinit")
@@ -62,10 +63,17 @@
 
         /* Walk entire namespace from the supplied root */
 
+ status = acpi_ex_enter_interpreter();
+ if (ACPI_FAILURE(status)) {
+ return status;
+ }
+
         status = acpi_walk_namespace (ACPI_TYPE_ANY, ACPI_ROOT_OBJECT,
                           ACPI_UINT32_MAX, acpi_ns_init_one_object,
                           &info, NULL);
 
+ acpi_ex_exit_interpreter();
+
         return (AE_OK);
 }
 
-
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This archive was generated by hypermail 2b29 : Sat Jul 07 2001 - 21:00:13 EST