Hi!
I've done some tests and here is what I figured out: the interrupts
assigned to the device controlled by the ahci driver keep going even
without my driver loaded and even with all my boards removed from
system physically. So it seems that everything ok.
But I have another question concerning interrupts:
Let's take the situation I described in my first and second posts - I
have a system with the PCI board which I develop driver for. This
board shares interrupt with the device controlled by ahci driver. The
question is why every interrupt I got on this line is interpreted by
my driver as the interrupt which belongs to it? Here is the code I
use:
=== CODE BELOW ===
to register ISR:
struct my_dev *board;
request_irq(board->irq, my_interrupt_handler, IRQF_SHARED, "my_module", board);
ISR:
static irqreturn_t my_interrupt_handler(int irq, void *dev_id)
{
struct my_dev *board;
int i, retval = IRQ_NONE;
// find out which board got an interrupt
for (i = 0; i < MAX_BOARDS; i++)
if (dev_id == &my_boards[i]) {
board = dev_id;
break;
}
// Check if interrupt was issued by another device (in case of shared
// interrupt line).
if (i == MAX_BOARDS)
goto handled;
if (board == NULL)
goto handled;
// if we are here then it's our interrupt
retval = IRQ_HANDLED;
/* here goes some checks on the device registers
to know if there is interrupts pending in it.
these checks are sure to be right. If there's no
interrupt, then debug message "no interrupt" is
printed.
*/
.......
/* here goes the interrupt handling, if the previous check
was successful
*/
.......
handled:
return retval;
}
=== CODE ABOVE ===
So, what do I have now. When no program touches my device (it is
idling) and the ahci driver is loaded I have this "no interrupt"
message in dmesg output 20-30 times per second. When some application
uses my device I have the proper printouts (the kind of interrupt and
so on) and bunch of these "no interrupt". When I install my board into
another PCI slot (and get another interrupt line) I never see these
"no interrupt" messages, but only the ones concerning to the actual
interrupt handling in my driver. Which indicates that driver works as
intended. The questions is why the dev_id parameter of
my_interrupt_handler() holds the data which belongs to one of the
boards controlled by my driver (which is the reason why the check in
the very beginning of ISR routine is passed)?
P.S.: I hope that you got what I tried to explain=) English is not my
native language=)
--
Denis
--
To unsubscribe from this list: send an email with
"unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx
Please read the FAQ at http://kernelnewbies.org/FAQ
