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Subject: Re: [PATCH 1/2]MSI(X) save/restore for suspend/resume
From: Shaohua Li <shaohua.li@intel.com>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Andrew Morton <akpm@osdl.org>,
       linux-pci <linux-pci@atrey.karlin.mff.cuni.cz>,
       lkml <linux-kernel@vger.kernel.org>, Greg <greg@kroah.com>,
       Rajesh Shah <rajesh.shah@intel.com>
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Date: Wed, 11 Jan 2006 09:17:19 +0800
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On Tue, 2006-01-10 at 13:28 -0700, Matthew Wilcox wrote:
> On Thu, Jan 05, 2006 at 08:58:00AM +0800, Shaohua Li wrote:
> > +	if ((pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)) <= 0 ||
> > +		dev->no_msi)
> 
> No assignments within conditionals, please.
Ok.

> 	pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
> 	if (pos <= 0 || dev->no_msi)
> 
> >  	u32		saved_config_space[16]; /* config space saved at suspend time */
> > +	void		*saved_cap_space[PCI_CAP_ID_MAX + 1]; /* ext config space saved at suspend time */
> >  	struct bin_attribute *rom_attr; /* attribute descriptor for sysfs ROM entry */
> ...
> >  #define  PCI_CAP_ID_MSIX	0x11	/* MSI-X */
> > +#define PCI_CAP_ID_MAX		PCI_CAP_ID_MSIX
> >  #define PCI_CAP_LIST_NEXT	1	/* Next capability in the list */
> 
> Rather than taking all this space in the pci_dev structure (even
> without CONFIG_PM), how about:
> 
> struct pci_cap_saved_state {
> 	struct pci_cap_saved_state *next;
> 	char cap_nr;
> 	char data[0];
> }
> 
> and then just add:
> 
> 	struct pci_cap_saved_state *saved_cap_space;
> 
> to the struct pci_dev?  One pointer, rather than (currently!) 12.
> That's an 88 byte saving per PCI device on 64-bit machines!
It's not that big, right? This will make things a little complex. How
about just define saved_cap_space[] with CONFIG_PM configured? Anyway,
if you insist on less space, I'm happy to change it.

Thanks,
Shaohua