Quoting Lorenzo Pieralisi (2018-12-03 09:18:59)

[+Stephen, Mike]

On Mon, Dec 03, 2018 at 04:38:46PM +0100, Miquel Raynal wrote:

quoted

Hi Lorenzo,

Lorenzo Pieralisi [off-list ref] wrote on Mon, 3 Dec 2018
10:27:08 +0000:

quoted

[+Rafael, Sudeep]

On Fri, Nov 23, 2018 at 03:18:24PM +0100, Miquel Raynal wrote:

quoted

Add suspend and resume callbacks. The priority of these are
"_noirq()", to workaround early access to the registers done by the
PCI core through the ->read()/->write() callbacks at resume time.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/pci/controller/pci-aardvark.c | 52 +++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 108b3f15c410..7ecf1ac4036b 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c

@@ -1108,6 +1108,55 @@ static int advk_pcie_setup_clk(struct advk_pcie *pcie)
  return ret;
 }
 
+static int __maybe_unused advk_pcie_suspend(struct device *dev)
+{
+ struct advk_pcie *pcie = dev_get_drvdata(dev);
+
+ advk_pcie_disable_phy(pcie);
+
+ clk_disable_unprepare(pcie->clk);  

I have noticed it is common practice, still, I would like to check whether
it is allowed to call functions that may sleep in a NOIRQ suspend/resume
callback ?

You are right this is weird. I double checked and for instance,
pcie-mediatek.c, pci-tegra.c and pci-imx6.c do the exact same thing.
There are probably other cases where drivers call functions that may
sleep from a NOIRQ context. I am interested to know if this is valid
and if not, what is the alternative?

I added Stephen and Mike, who along with Rafael can help us shed some
light into this, I do not have the necessary bits of info myself, I just
noticed.

Is the noirq phase of system suspend run with irqs disabled? Or just run
with the device irqs disabled? I thought it was the latter, which is
fine for this scenario because it's still running in a schedulable
context.


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