Re: Areca RAID driver remaining items?

From: erich
Date: Thu Feb 23 2006 - 06:49:39 EST


Dear Arjan van de Ven,

Thanks for your answer.
I will remove CONFIG_SCSI_ARCMSR_MSI in next patch.

If Linux can not assurent the contingous memory space allocating of "dma_alloc_coherent" .
When arcmsr get a physical ccb address from areca's firmware.
Does linux has any functions for converting of "bus to virtual" ?

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 5:56 PM
Subject: Re: Areca RAID driver remaining items?


On Thu, 2006-02-23 at 17:50 +0800, erich wrote:
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.


yes the reason for making this optional is clear, and Christoph also
understands that.

However the idea that Christoph is proposing is to not make it a compile
time option, but a runtime option. Compile-time is not very flexible,
especially not for linux distributions. Making it a module option means
it becomes runtime behavior, and the user can load the module like

modprobe aerca msi=0

and msi gets turned off. No need to recompile anything! That has many
advantages over a more inflexible (from the user view) compiletime-only
option.



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