macintosh/via-pmu: Don't clear shift register interrupt flag twice

Finn Thain · mpe · commit 7ad94699a94b · 2018-07-31T19:56:39.000+10:00
The shift register interrupt flag gets cleared in via_pmu_interrupt()
and once again in pmu_sr_intr(). Fix this theoretical race condition.

Tested-by: Stan Johnson &lt;userm57@yahoo.com&gt;
Signed-off-by: Finn Thain &lt;fthain@telegraphics.com.au&gt;
Reviewed-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
diff --git a/drivers/macintosh/via-pmu.c b/drivers/macintosh/via-pmu.c
@@ -1421,7 +1421,6 @@ pmu_sr_intr(void)
 
 	if (in_8(&via[B]) & TREQ) {
 		printk(KERN_ERR "PMU: spurious SR intr (%x)\n", in_8(&via[B]));
-		out_8(&via[IFR], SR_INT);
 		return NULL;
 	}
 	/* The ack may not yet be low when we get the interrupt */

Original file line number	Diff line number	Diff line change
`@@ -1421,7 +1421,6 @@ pmu_sr_intr(void)`
`1421`	`1421`
`1422`	`1422`	`if (in_8(&via[B]) & TREQ) {`
`1423`	`1423`	`printk(KERN_ERR "PMU: spurious SR intr (%x)\n", in_8(&via[B]));`
`1424`		`- out_8(&via[IFR], SR_INT);`
`1425`	`1424`	`return NULL;`
`1426`	`1425`	`}`
`1427`	`1426`	`/* The ack may not yet be low when we get the interrupt */`