3.9.0-rc1: kexec not working: root disk does not show up

[Vivek Goyal]

On Wed, Mar 13, 2013 at 06:53:16PM +0400, Konstantin Khlebnikov wrote:

[..]
> PCI: Don't try to disable Bus Master on disconnected PCI devices
> 
> From: Konstantin Khlebnikov <khlebnikov at openvz.org>
> 
> This is fix for commit 7897e6022761ace7377f0f784fca059da55f5d71 from v3.9-rc1
> ("PCI: Disable Bus Master unconditionally in pci_device_shutdown()")
> in turn that was fix for b566a22c23327f18ce941ffad0ca907e50a53d41 from v3.5-rc1
> ("PCI: disable Bus Master on PCI device shutdown")
> 
> Unfortunately fixing one bug uncovers another: after ->shutdown() device can be
> already disconnected from the bus and configuration space in no longer available
> 
> Link: https://lkml.org/lkml/2013/3/12/529
> Signed-off-by: Konstantin Khlebnikov <khlebnikov at openvz.org>
> Reported-by: Vivek Goyal <vgoyal at redhat.com>
> Cc: Bjorn Helgaas <bhelgaas at google.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
> ---
>  drivers/pci/pci-driver.c |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 1fa1e48..79277fb 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -390,9 +390,10 @@ static void pci_device_shutdown(struct device *dev)
>  
>  	/*
>  	 * Turn off Bus Master bit on the device to tell it to not
> -	 * continue to do DMA
> +	 * continue to do DMA. Don't touch devices in D3cold or unknown states.
>  	 */
> -	pci_clear_master(pci_dev);
> +	if (pci_dev->current_state <= PCI_D3hot)
> +		pci_clear_master(pci_dev);
>  }
>  
>  #ifdef CONFIG_PM

Hi,

Above patch fixed the issue on my box. Now I can kexec. Thanks.

Vivek