blob: 1cb706ff98f4b54a9abad2e34c63ff48a7048160 [file] [log] [blame]
From 684bd44cb76867b67f01db2b4685f91aaf36733e Mon Sep 17 00:00:00 2001
From: Paulo Zanoni <>
Date: Wed, 9 Oct 2013 16:39:57 -0300
Subject: drm/i915: increase the SWSCI DSLP default timeout to 50ms
The spec says the default timeout should be 2ms, but on my machine
this doesn't seem to be enough. Sometimes it works, sometimes I get
these messages when booting:
- SWSCI request timed out
- SWSCI request already in progress
And my guess is that the "already in progress" message is because the
first one is still happening.
I did some experiments on my machine (that has CONFIG_HZ=1000) and the
wait_for function usually takes 4-6 jiffies to finish, but I've seen
up to 9. So increase the timeout to 50ms. We only expect to wait for
the actual amount of time the operation takes, so even a huge timeout
shouldn't delay us more than what the hardware actually requires.
Cc: Jani Nikula <>
Signed-off-by: Paulo Zanoni <>
Reviewed-by: Jani Nikula <>
Signed-off-by: Daniel Vetter <>
(cherry picked from commit 4994aa8cc10177f620b096738be52eee8a181a9a)
Signed-off-by: Darren Hart <>
drivers/gpu/drm/i915/intel_opregion.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
index 2acf5cae20e4..904464023c8f 100644
--- a/drivers/gpu/drm/i915/intel_opregion.c
+++ b/drivers/gpu/drm/i915/intel_opregion.c
@@ -258,7 +258,9 @@ static int swsci(struct drm_device *dev, u32 function, u32 parm, u32 *parm_out)
/* Driver sleep timeout in ms. */
dslp = ioread32(&swsci->dslp);
if (!dslp) {
- dslp = 2;
+ /* The spec says 2ms should be the default, but it's too small
+ * for some machines. */
+ dslp = 50;
} else if (dslp > 500) {
/* Hey bios, trust must be earned. */
WARN_ONCE(1, "excessive driver sleep timeout (DSPL) %u\n", dslp);