ata: panic with new sysctl variable

[D. Rock]

Hi,

just noticed the new sysctl variable for ata. I just wanted to
use the new way for disabling DMA on my disk (has some strange
problems, even under windows).

Previously I just commented out the ata_dmainit() lines in
ata_disk.c, now I wanted to set it with sysctl:

sysctl -w hw.atamodes="pio,dma,dma,dma"

but this paniced my machine.

I later discovered that there is no sanity check during setting
the new modes: The machine in question didn't have a secondary
IDE controller, but the variables were set without a range check.

My solution was simple. Just use
sysctl -w hw.atamodes="pio,dma"

but I think, the ata driver should range check the settings.

Daniel


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Re: ata: panic with new sysctl variable

[Soren Schmidt]

It seems D. Rock wrote:
 Hi,
 
 just noticed the new sysctl variable for ata. I just wanted to
 use the new way for disabling DMA on my disk (has some strange
 problems, even under windows).
 
 Previously I just commented out the ata_dmainit() lines in
 ata_disk.c, now I wanted to set it with sysctl:
 
 sysctl -w hw.atamodes="pio,dma,dma,dma"
 
 but this paniced my machine.
 
 I later discovered that there is no sanity check during setting
 the new modes: The machine in question didn't have a secondary
 IDE controller, but the variables were set without a range check.
 
 My solution was simple. Just use
 sysctl -w hw.atamodes="pio,dma"
 
 but I think, the ata driver should range check the settings.

It does but not for the first two devices as the are kindof magic
in some sense. I'll commit the fix asap..

-Søren


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