Re: [PATCH] pci: print out DMA mask info

From: Yinghai Lu
Date: Thu Oct 09 2008 - 19:08:22 EST


Grant Grundler wrote:
> On Thu, Oct 09, 2008 at 02:51:32PM -0700, Yinghai Lu wrote:
>> On Thu, Oct 9, 2008 at 2:35 PM, Matthew Wilcox <matthew@xxxxxx> wrote:
>>> Why's that interesting to the sysadmin of the machine? To the driver
>>> writer, certainly. But what's the use of it to the people using the
>>> machine?
> ...
>> make linux kernel act like black box as other os?
>
> I don't understand your reply.
> If someone thinks linux is a black box, printing this message won't help them.
>
could find out easily why some driver doesn't set dma mask correctly.
like why
qlogic qla2xxx only set consistent to 64bit,
emulex lpfc not set consistent to 64bit
>
> "To flag use of bounce buffer or other suboptimal behaviors" could be debated.
>
>
> Regarding associating the output with other PCI messages, I'd hope the fact
> that the /sys entry is in the same directory as other sys files would be
> enough clue to associate those together. e.g.:
> grundler <2068>cd /sys/bus/pci/devices/0000\:01\:00.0/
> grundler <2069>ls
> broken_parity_status driver@ irq resource0 subsystem_device
> bus@ enable local_cpus resource1 subsystem_vendor
> class i2c-0/ modalias resource3 uevent
> config i2c-1/ power/ rom vendor
> device i2c-2/ resource subsystem@
>

add dma_mask coherent_dma_mask here?

YH
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