On 10/12/2017 04:09 PM, David Laight wrote:
From: Pankaj Dubey
Sent: 12 October 2017 08:55
In pcie-designware.c many places we are calling "usleep_range" which
are in atomic context. This patch fixes these potential BUGs and
replaces "usleep_range" with mdelay calls.

Signed-off-by: Pankaj Dubey <pankaj.du...@samsung.com>
---
  drivers/pci/dwc/pcie-designware.c | 8 ++++----
  drivers/pci/dwc/pcie-designware.h | 3 +--
  2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/dwc/pcie-designware.c 
b/drivers/pci/dwc/pcie-designware.c
index 88abddd..35d19b9 100644
--- a/drivers/pci/dwc/pcie-designware.c
+++ b/drivers/pci/dwc/pcie-designware.c
@@ -138,7 +138,7 @@ static void dw_pcie_prog_outbound_atu_unroll(struct dw_pcie 
*pci, int index,
                if (val & PCIE_ATU_ENABLE)
                        return;

-               usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+               mdelay(LINK_WAIT_IATU_MIN);
        }
Spinning for 9ms (possibly 10 times) isn't really a good idea.

Yes. It may not be a good idea, however in our experiment it never hit maximum retry count. I just converted usleep_range to mdelay keeping min time limitation as it is, though I am not sure, how do we arrived on these numbers in original code, may be Joao Pinto from Synopsys have some idea, I will try to do few experiment and try to find out what
is sufficient minimum time in our hardware for these mdelay.

Thanks,
Pankaj Dubey
        David





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