Ubuntu/CentOS guest instances in VMware sometimes come up with the boot error message:
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piix4_smbus 0000:00:007.3: Host SMBus controller not enabled!
This error is being caused because VMware doesn’t actually provide that level interface for CPU access, but Ubuntu try to load the kernel module anyway.
void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr)
{
if (q) {
unsigned long flags;
wq_read_lock_irqsave(&q->lock, flags);
__wake_up_common(q, mode, nr, 0);
wq_read_unlock_irqrestore(&q->lock, flags);
}
}
/ The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just wake everything up. If it’s an exclusive wakeup (nr_exclusive == small +ve number) then we wake all the non-exclusive tasks and one exclusive task.
There are circumstances in which we can try to wake a task which has already started to run but is not in state TASK_RUNNING. try_to_wake_up() returns zero in this (rare) case, and we handle it by contonuing to scan the queue. /
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static inline void __wake_up_common (wait_queue_head_t *q, unsigned int mode, int nr_exclusive, const int sync)
/ 唤醒一个进程，将它放到运行队列中，如果它还不在运行队列的话。"当前"进程总是在运行队列中的（except when the actual re-schedule is in progress)，and as such you’re allowed to do the simpler “current->state = TASK_RUNNING” to mark yourself runnable without the overhead of this. /
static int __init char8139_init(void)
{
int result;
PDBG("hello. init.\n");
/* register our char device */
result = register_chrdev(char8139_major, "char8139", &char8139_fops);
if (result < 0) {
PDBG("Cannot allocate major device number!\n");
return result;
}
/* register_chrdev() will assign a major device number and return if it called
* with "major" parameter set to 0 */
if(char8139_major == 0)
char8139_major=result;
/* allocate some kernel memory we need */
buffer = (unsigned char*)(kmalloc(CHAR8139_BUFFER_SIZE, GFP_KERNEL));
if (!buffer) {
PDBG("Cannot allocate memory!\n");
result = -ENOMEM;
goto init_fail;
}
memset(buffer, 0, CHAR8139_BUFFER_SIZE);
p_buf = buffer;
return 0; /* everything's ok */
init_fail:
char8139_exit();
return result;
}
#define DEFAULT_MAJOR 145 /* data structure used by our driver */
int char8139_major=DEFAULT_MAJOR; /* major device number. if initial value is 0,
* the kernel will dynamically assign a major device
* number in register_chrdev() */
int char8139_open(struct inode *node, struct file *flip)
{
int type = MINOR(node->i_rdev)>>4;
int num = MINOR(node->i_rdev) & 0x0F;
/* put some char in buffer to reflect the minor device number */
*buffer=(unsigned char)('0');
*(buffer+1)=(unsigned char)('x');
*(buffer+2)=(unsigned char)('0'+type);
*(buffer+3)=(unsigned char)('0'+num);
*(buffer+4)=(unsigned char)('\n');
data_size+=5;
PDBG("Ok. Find treasure! 8139 I/O port base: %x\n", detect_8139_io_port());
PDBG("OK. Find treasure! 8139 I/O memory base address: %lx\n",
detect_8139_io_mem());
MOD_INC_USE_COUNT;
return 0;
}
