On Wed, Dec 02, 2015 at 01:13:16PM +0530, Sanjeev Sharma wrote:
> From: David Mueller <dave.mueller@xxxxxx>
>
> If additional PCIe switch get connected between the
> host and the NIC,the kernel crashes with "BUG:
> scheduling while atomic". To handle this we need to
> call mdelay() instead of usleep_range().
>
> This is currently called from atomic context through
> pci_config_{read,write).
>
> For more detail please refer bugzilla.kernel.org, Bug
> 100031
Bug reports have URLs; please use them. I'll save you the trouble:
Link: https://bugzilla.kernel.org/show_bug.cgi?id=100031
In that bug report, I said: "My first question on the list will be:
Besides imx6, there are five other DesignWare-based drivers, and
imx6_pcie_link_up() looks nothing like the other
pcie_host_ops.link_up() methods. We need to explain why imx6 is
special, and whether all the .link_up() methods can be made similar."
The only response was that i.MX6 is special because of a hardware bug,
so we need to start at Gen1, wait, try to change to Gen2, etc. That
all sounds like work that should be done in
imx6_pcie_establish_link().
This patch doesn't seem to make anything *worse*, so I might take it
anyway, but I'm a little disappointed that we didn't make any progress
toward making imx6 more like the other drivers. I know this sounds
pedantic, but it's a lot easier to let things slowly diverge than it
is to keep them uniform, and bugs hide in differences like this.
> Signed-off-by: David Mueller <dave.mueller@xxxxxx>
> Signed-off-by: Sanjeev Sharma <sanjeev_sharma@xxxxxxxxxx>
>
> Changes in v2:
> -order of signoff has been change
> -Author of patch has been change
> -A mdelay(1000) is different timescale than
> a usleep(1000).change it to correct scale i.e mdelay(1)
> -updated comment
> ---
> drivers/pci/host/pci-imx6.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
> index 233a196..c03527f 100644
> --- a/drivers/pci/host/pci-imx6.c
> +++ b/drivers/pci/host/pci-imx6.c
> @@ -499,7 +499,7 @@ static int imx6_pcie_link_up(struct pcie_port *pp)
> * Wait a little bit, then re-check if the link finished
> * the training.
> */
> - usleep_range(1000, 2000);
> + mdelay(1);
> }
> /*
> * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
> --
> 1.7.11.7
>
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