2.6.30.5-rtai hits a kernel BUG when ctrl_type= is specified.
Investigation of in-kernel users of module_param_array(charp) implies
that they all use zero'd out arrays, in contrast to our initialized array.
the BUG is that param_set_charp attempts to kfree the old value.
Revamp how stepgen treats ctrl_type so that an empty or unspecified value
is treated like 'v', so that the initial ctrl_type can be uninitialized.
This has the side effect of making empty ctrl_types (e.g., ctrl_type=p,v,,v)
indicate position control.
---
I verified that this still works OK on sim and 2.6.12-magma (breezy! but
the only realtime system I had handy); does it fix stepgen ctrl_type
with your kernel?
src/hal/components/stepgen.c | 21 ++++++++++++++-------
1 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/src/hal/components/stepgen.c b/src/hal/components/stepgen.c
index b0fa061..9dafce1 100644
--- a/src/hal/components/stepgen.c
+++ b/src/hal/components/stepgen.c
@@ -312,7 +312,7 @@ MODULE_DESCRIPTION("Step Pulse Generator for EMC HAL");
MODULE_LICENSE("GPL");
int step_type[MAX_CHAN] = { -1, -1, -1, -1, -1, -1, -1, -1 };
RTAPI_MP_ARRAY_INT(step_type,MAX_CHAN,"stepping types for up to 8 channels");
-const char *ctrl_type[MAX_CHAN] = { "p", "p", "p", "p", "p", "p", "p", "p" };
+const char *ctrl_type[MAX_CHAN];
RTAPI_MP_ARRAY_STRING(ctrl_type,MAX_CHAN,"control type (pos or vel) for up to
8 channels");
/***********************************************************************
@@ -418,6 +418,8 @@ static long old_dtns; /* update_freq funct
period in nsec */
static double dt; /* update_freq period in seconds */
static double recip_dt; /* recprocal of period, avoids divides
*/
+typedef enum CONTROL { POSITION, VELOCITY, INVALID } CONTROL;
+
/***********************************************************************
* LOCAL FUNCTION DECLARATIONS *
************************************************************************/
@@ -426,6 +428,8 @@ static int export_stepgen(int num, stepgen_t * addr, int
step_type, int pos_mode
static void make_pulses(void *arg, long period);
static void update_freq(void *arg, long period);
static void update_pos(void *arg, long period);
+static CONTROL parse_ctrl_type(const char *ctrl);
+
/***********************************************************************
* INIT AND EXIT CODE *
@@ -442,11 +446,7 @@ int rtapi_app_main(void)
step_type[n], n);
return -1;
}
- if ((ctrl_type[n][0] == 'p' ) || (ctrl_type[n][0] == 'P')) {
- ctrl_type[n] = "p";
- } else if ((ctrl_type[n][0] == 'v' ) || (ctrl_type[n][0] == 'V')) {
- ctrl_type[n] = "v";
- } else {
+ if(parse_ctrl_type(ctrl_type[n]) == INVALID) {
rtapi_print_msg(RTAPI_MSG_ERR,
"STEPGEN: ERROR: bad control type '%s' for axis %i
(must be 'p' or 'v')\n",
ctrl_type[n], n);
@@ -490,7 +490,7 @@ int rtapi_app_main(void)
for (n = 0; n < num_chan; n++) {
/* export all vars */
retval = export_stepgen(n, &(stepgen_array[n]),
- step_type[n], (ctrl_type[n][0] == 'p'));
+ step_type[n], (parse_ctrl_type(ctrl_type[n]) == POSITION));
if (retval != 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"STEPGEN: ERROR: stepgen %d var export failed\n", n);
@@ -1187,3 +1187,10 @@ static int export_stepgen(int num, stepgen_t * addr, int
step_type, int pos_mode
rtapi_set_msg_level(msg);
return 0;
}
+
+static CONTROL parse_ctrl_type(const char *ctrl)
+{
+ if(!ctrl || !*ctrl || *ctrl == 'p' || *ctrl == 'P') return POSITION;
+ if(*ctrl == 'v' || *ctrl == 'V') return VELOCITY;
+ return INVALID;
+}
--
1.6.6.62.g584f3
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