r8169: prevent excessive busy-waiting
The MII registers read/write function blindly busy waits for an
amount of 1000 us (1 ms), then up to 200 ms. These functions are
called from irq disabled context. Depending on the clock management,
it triggers lost ticks events. Since the value is way above the
standard delay required for mii register access, it strangely looks
like a bandaid against posted writes.
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=5947
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index 2e1bed15..a81338b 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -484,13 +484,12 @@
int i;
RTL_W32(PHYAR, 0x80000000 | (RegAddr & 0xFF) << 16 | value);
- udelay(1000);
- for (i = 2000; i > 0; i--) {
+ for (i = 20; i > 0; i--) {
/* Check if the RTL8169 has completed writing to the specified MII register */
if (!(RTL_R32(PHYAR) & 0x80000000))
break;
- udelay(100);
+ udelay(25);
}
}
@@ -499,15 +498,14 @@
int i, value = -1;
RTL_W32(PHYAR, 0x0 | (RegAddr & 0xFF) << 16);
- udelay(1000);
- for (i = 2000; i > 0; i--) {
+ for (i = 20; i > 0; i--) {
/* Check if the RTL8169 has completed retrieving data from the specified MII register */
if (RTL_R32(PHYAR) & 0x80000000) {
value = (int) (RTL_R32(PHYAR) & 0xFFFF);
break;
}
- udelay(100);
+ udelay(25);
}
return value;
}