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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2009-12-11 22:00:57 -0800
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2009-12-11 23:55:31 -0800
commit4e8d340daac46cec8a0f8b3b0f228274fac913ba (patch)
treef33f60499567f0ef54e4482956a74cad9106ccdb /drivers/input/serio/i8042.c
parent7105d2ea73e1391b681d0e1212c42f561c64d429 (diff)
downloadlinux-4e8d340daac46cec8a0f8b3b0f228274fac913ba.tar.bz2
Input: i8042 - fix locking in interrupt routine
We need to protect not only i8042 status and data register from concurrent access from IRQ 1 and 12 but the rest of the shared state as well, so let's move release of i8042_lock in i8042_interrupt() a little bit further down. Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input/serio/i8042.c')
-rw-r--r--drivers/input/serio/i8042.c34
1 files changed, 26 insertions, 8 deletions
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 1df02d25aca5..634da68f7f35 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -369,6 +369,25 @@ static void i8042_stop(struct serio *serio)
}
/*
+ * i8042_filter() filters out unwanted bytes from the input data stream.
+ * It is called from i8042_interrupt and thus is running with interrupts
+ * off and i8042_lock held.
+ */
+static bool i8042_filter(unsigned char data, unsigned char str)
+{
+ if (unlikely(i8042_suppress_kbd_ack)) {
+ if ((~str & I8042_STR_AUXDATA) &&
+ (data == 0xfa || data == 0xfe)) {
+ i8042_suppress_kbd_ack--;
+ dbg("Extra keyboard ACK - filtered out\n");
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/*
* i8042_interrupt() is the most important function in this driver -
* it handles the interrupts from the i8042, and sends incoming bytes
* to the upper layers.
@@ -381,9 +400,11 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
unsigned char str, data;
unsigned int dfl;
unsigned int port_no;
+ bool filtered;
int ret = 1;
spin_lock_irqsave(&i8042_lock, flags);
+
str = i8042_read_status();
if (unlikely(~str & I8042_STR_OBF)) {
spin_unlock_irqrestore(&i8042_lock, flags);
@@ -391,8 +412,8 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
ret = 0;
goto out;
}
+
data = i8042_read_data();
- spin_unlock_irqrestore(&i8042_lock, flags);
if (i8042_mux_present && (str & I8042_STR_AUXDATA)) {
static unsigned long last_transmit;
@@ -447,14 +468,11 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
dfl & SERIO_PARITY ? ", bad parity" : "",
dfl & SERIO_TIMEOUT ? ", timeout" : "");
- if (unlikely(i8042_suppress_kbd_ack))
- if (port_no == I8042_KBD_PORT_NO &&
- (data == 0xfa || data == 0xfe)) {
- i8042_suppress_kbd_ack--;
- goto out;
- }
+ filtered = i8042_filter(data, str);
+
+ spin_unlock_irqrestore(&i8042_lock, flags);
- if (likely(port->exists))
+ if (likely(port->exists && !filtered))
serio_interrupt(port->serio, data, dfl);
out: