Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1337096 > unrolled thread

RE: [PATCH] PCI: imx6:don't sleep in atomic context

Started by"Sharma, Sanjeev" <Sanjeev_Sharma@mentor.com>
First post2016-02-18 08:20 +0100
Last post2016-02-19 10:30 +0100
Articles 3 — 2 participants

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  RE: [PATCH] PCI: imx6:don't sleep in atomic context "Sharma, Sanjeev" <Sanjeev_Sharma@mentor.com> - 2016-02-18 08:20 +0100
    Re: [PATCH] PCI: imx6:don't sleep in atomic context Bjorn Helgaas <helgaas@kernel.org> - 2016-02-18 16:10 +0100
      RE: [PATCH] PCI: imx6:don't sleep in atomic context "Sharma, Sanjeev" <Sanjeev_Sharma@mentor.com> - 2016-02-19 10:30 +0100

#1337096 — RE: [PATCH] PCI: imx6:don't sleep in atomic context

From"Sharma, Sanjeev" <Sanjeev_Sharma@mentor.com>
Date2016-02-18 08:20 +0100
SubjectRE: [PATCH] PCI: imx6:don't sleep in atomic context
Message-ID<r3r2y-229-5@gated-at.bofh.it>
-----Original Message-----
From: Bjorn Helgaas [mailto:helgaas@kernel.org] 
Sent: Thursday, January 07, 2016 3:35 AM
To: Sharma, Sanjeev
Cc: Richard.Zhu@freescale.com; l.stach@pengutronix.de; bhelgaas@google.com; linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; David Mueller
Subject: Re: [PATCH] PCI: imx6:don't sleep in atomic context

Hi Sanjeev,

On Mon, Nov 09, 2015 at 04:18:00PM +0530, Sanjeev Sharma wrote:
> 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().
> 
> For more detail please refer bugzilla.kernel.org, Bug
> 100031
> 
> Signed-off-by: Sanjeev Sharma <sanjeev_sharma@mentor.com>
> Signed-off-by: David Mueller <dave.mueller@gmx.ch>

I'm dropping this for now because we've been kicking around the same solution (with tweaks to the mdelay amount) since June, but no progress on the *real* issue, which is that imx6_pcie_link_up() should never wait; it should simply return the link status.

I'm pretty sure the amount of time I've spent looking into this would have been enough to make some progress on that underlying issue.

Bjorn

Ok ! please share the change you are planning to implement. 

Sanjeev Sharma 
> ---
>  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..9769b13 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(1000);
>  	}
>  	/*
>  	 * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
> --
> 1.7.11.7
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" 
> in the body of a message to majordomo@vger.kernel.org More majordomo 
> info at  http://vger.kernel.org/majordomo-info.html

[toc] | [next] | [standalone]

#1337438

FromBjorn Helgaas <helgaas@kernel.org>
Date2016-02-18 16:10 +0100
Message-ID<r3ynn-7re-1@gated-at.bofh.it>
In reply to#1337096
On Thu, Feb 18, 2016 at 07:17:41AM +0000, Sharma, Sanjeev wrote:
> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas@kernel.org] 
> Sent: Thursday, January 07, 2016 3:35 AM
> To: Sharma, Sanjeev
> Cc: Richard.Zhu@freescale.com; l.stach@pengutronix.de; bhelgaas@google.com; linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; David Mueller
> Subject: Re: [PATCH] PCI: imx6:don't sleep in atomic context
> 
> Hi Sanjeev,
> 
> On Mon, Nov 09, 2015 at 04:18:00PM +0530, Sanjeev Sharma wrote:
> > 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().
> > 
> > For more detail please refer bugzilla.kernel.org, Bug
> > 100031
> > 
> > Signed-off-by: Sanjeev Sharma <sanjeev_sharma@mentor.com>
> > Signed-off-by: David Mueller <dave.mueller@gmx.ch>
> 
> I'm dropping this for now because we've been kicking around the same solution (with tweaks to the mdelay amount) since June, but no progress on the *real* issue, which is that imx6_pcie_link_up() should never wait; it should simply return the link status.
> 
> I'm pretty sure the amount of time I've spent looking into this would have been enough to make some progress on that underlying issue.
> 
> Bjorn
> 
> Ok ! please share the change you are planning to implement. 

I didn't mean I personally was going to do this.  But I think Lucas
stepped up and did it:

https://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/commit/?h=pci/host-imx6&id=4d107d3b5a686b5834e533a00b73bf7b1cf59df7

> > ---
> >  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..9769b13 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(1000);
> >  	}
> >  	/*
> >  	 * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
> > --
> > 1.7.11.7
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pci" 
> > in the body of a message to majordomo@vger.kernel.org More majordomo 
> > info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

[toc] | [prev] | [next] | [standalone]

#1338011

From"Sharma, Sanjeev" <Sanjeev_Sharma@mentor.com>
Date2016-02-19 10:30 +0100
Message-ID<r3PxU-2Sp-9@gated-at.bofh.it>
In reply to#1337438
-----Original Message-----
From: Bjorn Helgaas [mailto:helgaas@kernel.org] 
Sent: Thursday, February 18, 2016 8:39 PM
To: Sharma, Sanjeev
Cc: Richard.Zhu@freescale.com; l.stach@pengutronix.de; bhelgaas@google.com; linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; David Mueller
Subject: Re: [PATCH] PCI: imx6:don't sleep in atomic context

On Thu, Feb 18, 2016 at 07:17:41AM +0000, Sharma, Sanjeev wrote:
> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas@kernel.org]
> Sent: Thursday, January 07, 2016 3:35 AM
> To: Sharma, Sanjeev
> Cc: Richard.Zhu@freescale.com; l.stach@pengutronix.de; 
> bhelgaas@google.com; linux-pci@vger.kernel.org; 
> linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; 
> David Mueller
> Subject: Re: [PATCH] PCI: imx6:don't sleep in atomic context
> 
> Hi Sanjeev,
> 
> On Mon, Nov 09, 2015 at 04:18:00PM +0530, Sanjeev Sharma wrote:
> > 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().
> > 
> > For more detail please refer bugzilla.kernel.org, Bug
> > 100031
> > 
> > Signed-off-by: Sanjeev Sharma <sanjeev_sharma@mentor.com>
> > Signed-off-by: David Mueller <dave.mueller@gmx.ch>
> 
> I'm dropping this for now because we've been kicking around the same solution (with tweaks to the mdelay amount) since June, but no progress on the *real* issue, which is that imx6_pcie_link_up() should never wait; it should simply return the link status.
> 
> I'm pretty sure the amount of time I've spent looking into this would have been enough to make some progress on that underlying issue.
> 
> Bjorn
> 
> Ok ! please share the change you are planning to implement. 

I didn't mean I personally was going to do this.  But I think Lucas stepped up and did it:

https://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/commit/?h=pci/host-imx6&id=4d107d3b5a686b5834e533a00b73bf7b1cf59df7

Thanks Bjorn 

code look ok !

> > ---
> >  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..9769b13 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(1000);
> >  	}
> >  	/*
> >  	 * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
> > --
> > 1.7.11.7
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pci" 
> > in the body of a message to majordomo@vger.kernel.org More majordomo 
> > info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" 
> in the body of a message to majordomo@vger.kernel.org More majordomo 
> info at  http://vger.kernel.org/majordomo-info.html

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web