Re: Areca RAID driver remaining items?

From: erich
Date: Thu Feb 23 2006 - 04:48:23 EST


Dear Arjan van de Ven,

The following contex is coming from comment of Christoph Hellwig.

- msi should be a module options if at all, but defintitly not
a config options

#ifdef CONFIG_SCSI_ARCMSR_MSI
if (!pci_enable_msi(pci_device))
pACB->acb_flags |= ACB_F_HAVE_MSI;
#endif

I make an option config for prevent some mainboards hang up if arcmsr enable msi function.
Areca RAID controller is bridged hardware.
There were a lots of mainboards had wrong IRQ routing table issue with it.
If somebody meet this issue and people can enable msi function to fix its hardware bug.
But unfortunately I found some mainboards will hang up if I always enable this function in my lab.
To avoid this issue, I do an option for this case.

But Christoph Hellwig give me comment with it.

Best Regards
Erich Chen

----- Original Message ----- From: "Arjan van de Ven" <arjan@xxxxxxxxxxxxx>
To: "erich" <erich@xxxxxxxxxxxx>
Cc: "Christoph Hellwig" <hch@xxxxxxxxxxxxx>; <linux-scsi@xxxxxxxxxxxxxxx>; <linux-kernel@xxxxxxxxxxxxxxx>; <billion.wu@xxxxxxxxxxxx>; <alan@xxxxxxxxxxxxxxxxxxx>; <akpm@xxxxxxxx>; <oliver@xxxxxxxxxx>
Sent: Thursday, February 23, 2006 4:25 PM
Subject: Re: Areca RAID driver remaining items?


On Thu, 2006-02-23 at 14:27 +0800, erich wrote:
Dear Christoph Hellwig,

I have figure out your comments about "remove internal queueing" and "remove
odd ioctl".
But about "hardware datastructures", areca's firmware spec is need to get a
trunk of contingous memory space under 4G.
In 64bit platform arcmsr need to make sure all ccbs have same of
ccb_phyaddr_hi32 physical address.
If arcmsr use dma_pool_alloc do a separate dma mapping.
Is there any method to avoid ccbs pool cross 4G segment?

the pci mapping layer prevents that already entirely; there is a LOT of
hardware that cannot deal with segments crossing 4G boundaries, so much
in fact that it's now generically disabled.


In some mainboard if I always enable msi function, it will cause system hang
up.
If it is not a config option, do you have any idea to avoid this issue?

how about a module option (module_param)?



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