From 4994aa8cc10177f620b096738be52eee8a181a9a Mon Sep 17 00:00:00 2001 From: Paulo Zanoni Date: Wed, 9 Oct 2013 16:39:57 -0300 Subject: [PATCH] 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 --- 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); -- 2.30.2