sdl: increase default worker thread size.

This fixes a mysterious, long-standing crash that's been bothering me on
ipod6g for ages: a silent stack overflow in the sound mixing thread (which
is triggered upon loading a new sound, apparently) will thrash the memory
which is located directly before it in the address space.

In this case, it was the SDL_ButtonState variable which stores the mouse
button state that was being trashed. This was manifesting itself by making
the player always run forward, since MOUSE2 is mapped to +forward by
default.

Fix this by quadrupling the stack size of SDL-spawned threads (not the main
thread) from 1 KB to 4 KB.

Change-Id: I2d7901b7cee1e3ceb1ccdebb38d4ac5b7ea730e1

1 files changed, 7 insertions, 2 deletions

diff --git a/apps/plugins/sdl/src/thread/rockbox/SDL_systhread.c b/apps/plugins/sdl/src/thread/rockbox/SDL_systhread.c
index b9bd8735d3..d393e50e14 100644
--- a/apps/plugins/sdl/src/thread/rockbox/SDL_systhread.c
+++ b/apps/plugins/sdl/src/thread/rockbox/SDL_systhread.c
@@ -42,20 +42,25 @@ static void rbsdl_runthread(void)
     SDL_RunThread(args);
 }
 
+#define RBSDL_THREAD_STACK_SIZE (DEFAULT_STACK_SIZE * 4)
 #define MAX_THREAD 4
 static char names[MAX_THREAD][16];
-static long stacks[MAX_THREAD][DEFAULT_STACK_SIZE / sizeof(long)];
+static long stacks[MAX_THREAD][RBSDL_THREAD_STACK_SIZE / sizeof(long)];
 
 int SDL_SYS_CreateThread(SDL_Thread *thread, void *args)
 {
     static int threadnum = 0;
+
+    if(threadnum >= MAX_THREAD)
+        return -1;
+
     snprintf(names[threadnum], 16, "sdl_%d", threadnum);
 
     while(global_args) rb->yield(); /* busy wait, pray that this works */
 
     global_args = args;
 
-    thread->handle = rb->create_thread(rbsdl_runthread, stacks[threadnum], DEFAULT_STACK_SIZE,
+    thread->handle = rb->create_thread(rbsdl_runthread, stacks[threadnum], RBSDL_THREAD_STACK_SIZE,
                                        0, names[threadnum] /* collisions allowed? */
                                        IF_PRIO(, PRIORITY_BUFFERING) // this is used for sound mixing
                                        IF_COP(, CPU));