Hi Geert,

On Sunday 28 February 2016 09:55:32 Geert Uytterhoeven wrote:

On Sat, Feb 27, 2016 at 2:53 AM, Laurent Pinchart wrote:

quoted

After rebasing this series on top of Simon's latest devel branch, I'm
experiencing hard system freezes when using the VSP.

Is this due to the rebasing? Did it work in
renesas-drivers-2016-02-16-v4.5-rc4 or renesas-drivers-2016-02-23-v4.5-rc5?

I thought it was, but after further investigations I've been unable to get it
working at all even on my older branches, so I think the problem has always
been there.

quoted

What makes the problem curious is that PM runtime works fine when the VSP
instances are probed, the A3VP power domain is turned on and off correctly
for each instance. However, after booting the system, if I try to RPM
resume the device, the system hangs.

I've traced this (using printk debugging) down to the SYSCISCR write in
rcar_sysc_power(). The value written is 0x00000200, which corresponds to
the A3VP power domain, and the resume request completion wait loop
doesn't time out.

So the second write to SYSCISCR in that function locks up the system?

Correct, and only after the kernel has booted, there's a bunch of calls to
rcar_sysc_power() to enable/disable the A3VP power domain at boot time when
the vsp devices are probed, and those don't cause any issue.

quoted

Does this ring any bell ? Do you have a more recent version of this patch
series that I could try ?

No clue, and no more recent version available yet.

What do I need to reproduce this?

Compile

git://linuxtv.org/pinchartl/media.git drm/du/vsp1-kms/boards

(.config attached), boot it, and run

# cat /dev/video0

You can apply the following patch to see what's going on.

diff --git a/drivers/soc/renesas/pm-rcar.c b/drivers/soc/renesas/pm-rcar.c
index d1bf8c231540..4a5f00d7f84d 100644
--- a/drivers/soc/renesas/pm-rcar.c
+++ b/drivers/soc/renesas/pm-rcar.c

@@ -139,6 +139,9 @@ static int rcar_sysc_power(const struct rcar_sysc_ch *sysc_ch, bool on)
 	int ret = 0;
 	int k;
 
+	if (sysc_ch->isr_bit == 9)
+		printk(KERN_INFO "%s(A3VP, %s)\n", __func__, on ? "on" : "off");
+
 	spin_lock_irqsave(&rcar_sysc_lock, flags);
 
 	iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);

@@ -172,7 +175,16 @@ static int rcar_sysc_power(const struct rcar_sysc_ch *sysc_ch, bool on)
 	if (k == SYSCISR_RETRIES)
 		ret = -EIO;
 
+	if (sysc_ch->isr_bit == 9) {
+		udelay(5000);
+		printk(KERN_INFO "%s: will write to SYSISCR\n", __func__);
+		udelay(5000);
+	}
 	iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);
+	if (sysc_ch->isr_bit == 9) {
+		udelay(5000);
+		printk(KERN_INFO "%s: wrote to SYSISCR\n", __func__);
+	}
 
  out:
 	spin_unlock_irqrestore(&rcar_sysc_lock, flags);

On my system it prints the following messages during boot when probing the vsp
instances.

[    0.528433] rcar_sysc_power(A3VP, off)
[    0.535317] rcar_sysc_power: will write to SYSISCR
[    0.547713] rcar_sysc_power: wrote to SYSISCR
[    0.549910] rcar_sysc_power(A3VP, on)
[    0.556759] rcar_sysc_power: will write to SYSISCR
[    0.569155] rcar_sysc_power: wrote to SYSISCR
[    0.571386] rcar_sysc_power(A3VP, off)
[    0.578270] rcar_sysc_power: will write to SYSISCR
[    0.590665] rcar_sysc_power: wrote to SYSISCR
[    0.592857] rcar_sysc_power(A3VP, on)
[    0.599698] rcar_sysc_power: will write to SYSISCR
[    0.612094] rcar_sysc_power: wrote to SYSISCR
[    0.614310] rcar_sysc_power(A3VP, off)
[    0.621197] rcar_sysc_power: will write to SYSISCR
[    0.633592] rcar_sysc_power: wrote to SYSISCR
[    0.635783] rcar_sysc_power(A3VP, on)
[    0.642625] rcar_sysc_power: will write to SYSISCR
[    0.655020] rcar_sysc_power: wrote to SYSISCR
[    0.657237] rcar_sysc_power(A3VP, off)
[    0.664120] rcar_sysc_power: will write to SYSISCR
[    0.676515] rcar_sysc_power: wrote to SYSISCR
[    0.678706] rcar_sysc_power(A3VP, on)
[    0.685550] rcar_sysc_power: will write to SYSISCR
[    0.697945] rcar_sysc_power: wrote to SYSISCR
[    0.700133] rcar_sysc_power(A3VP, off)
[    0.707015] rcar_sysc_power: will write to SYSISCR
[    0.719410] rcar_sysc_power: wrote to SYSISCR
[    0.721736] rcar_sysc_power(A3VP, on)
[    0.728583] rcar_sysc_power: will write to SYSISCR
[    0.740978] rcar_sysc_power: wrote to SYSISCR
[    0.743213] rcar_sysc_power(A3VP, off)
[    0.750099] rcar_sysc_power: will write to SYSISCR
[    0.762495] rcar_sysc_power: wrote to SYSISCR
[    0.765445] rcar_sysc_power(A3VP, on)
[    0.772294] rcar_sysc_power: will write to SYSISCR
[    0.784689] rcar_sysc_power: wrote to SYSISCR
[    0.786897] rcar_sysc_power(A3VP, off)
[    0.793783] rcar_sysc_power: will write to SYSISCR
[    0.806178] rcar_sysc_power: wrote to SYSISCR
[    0.808369] rcar_sysc_power(A3VP, on)
[    0.815211] rcar_sysc_power: will write to SYSISCR
[    0.827606] rcar_sysc_power: wrote to SYSISCR
[    0.829845] rcar_sysc_power(A3VP, off)
[    0.836733] rcar_sysc_power: will write to SYSISCR
[    0.849128] rcar_sysc_power: wrote to SYSISCR
[    0.851985] rcar_sysc_power(A3VP, on)
[    0.858829] rcar_sysc_power: will write to SYSISCR
[    0.871224] rcar_sysc_power: wrote to SYSISCR
[    0.873435] rcar_sysc_power(A3VP, off)
[    0.880323] rcar_sysc_power: will write to SYSISCR
[    0.892719] rcar_sysc_power: wrote to SYSISCR
[    0.894911] rcar_sysc_power(A3VP, on)
[    0.901772] rcar_sysc_power: will write to SYSISCR
[    0.914168] rcar_sysc_power: wrote to SYSISCR
[    0.916395] rcar_sysc_power(A3VP, off)
[    0.923278] rcar_sysc_power: will write to SYSISCR
[    0.935673] rcar_sysc_power: wrote to SYSISCR
[    0.938275] rcar_sysc_power(A3VP, on)
[    0.945129] rcar_sysc_power: will write to SYSISCR
[    0.957525] rcar_sysc_power: wrote to SYSISCR
[    0.959729] rcar_sysc_power(A3VP, off)
[    0.966612] rcar_sysc_power: will write to SYSISCR
[    0.979008] rcar_sysc_power: wrote to SYSISCR
[    0.981204] rcar_sysc_power(A3VP, on)
[    0.988044] rcar_sysc_power: will write to SYSISCR
[    1.000440] rcar_sysc_power: wrote to SYSISCR
[    1.002660] rcar_sysc_power(A3VP, off)
[    1.009546] rcar_sysc_power: will write to SYSISCR
[    1.021941] rcar_sysc_power: wrote to SYSISCR
[    1.024540] rcar_sysc_power(A3VP, on)
[    1.031383] rcar_sysc_power: will write to SYSISCR
[    1.043778] rcar_sysc_power: wrote to SYSISCR
[    1.045980] rcar_sysc_power(A3VP, off)
[    1.052865] rcar_sysc_power: will write to SYSISCR
[    1.065261] rcar_sysc_power: wrote to SYSISCR
[    1.067450] rcar_sysc_power(A3VP, on)
[    1.074292] rcar_sysc_power: will write to SYSISCR
[    1.086687] rcar_sysc_power: wrote to SYSISCR
[    1.088910] rcar_sysc_power(A3VP, off)
[    1.095792] rcar_sysc_power: will write to SYSISCR
[    1.108187] rcar_sysc_power: wrote to SYSISCR
[    1.110781] rcar_sysc_power(A3VP, on)
[    1.117628] rcar_sysc_power: will write to SYSISCR
[    1.130023] rcar_sysc_power: wrote to SYSISCR
[    1.132224] rcar_sysc_power(A3VP, off)
[    1.139106] rcar_sysc_power: will write to SYSISCR
[    1.151501] rcar_sysc_power: wrote to SYSISCR


When I cat /dev/video0 I get the following messages in the kernel log

/ # cat /dev/video0
[    4.673226] rcar_sysc_power(A3VP, on)
[    4.680816] rcar_sysc_power: will write to SYSISCR

and the system then freezes.

-- 
Regards,

Laurent Pinchart