Hi!
Please CC me, as I'm currently not subscribed to this list, thx.
Attached patch will add above mentioned Laptop Model to whitelist for both
pata_ali and alim15x3, as it is correctly detected as 40-wire connected but
this cable is short enough to still do transfers higher than UDMA33.
Don't know if this is also true for other S1800 Laptops cause I own only one.
I hope I did this correctly as this is my first Patch Mail to LKML :)
--
Greetings
Daniel Exner
On Wed, 29 Aug 2007 23:41:13 +0200
Daniel Exner <[email protected]> wrote:
> Hi!
>
> Please CC me, as I'm currently not subscribed to this list, thx.
>
> Attached patch will add above mentioned Laptop Model to whitelist for both
> pata_ali and alim15x3, as it is correctly detected as 40-wire connected but
> this cable is short enough to still do transfers higher than UDMA33.
> Don't know if this is also true for other S1800 Laptops cause I own only one.
Looks good to me - does need a Signed-off-by: line however
Alan Cox wrote:
> Daniel Exner <[email protected]> wrote:
>> Attached patch will add above mentioned Laptop Model to whitelist for both
>> pata_ali and alim15x3, as it is correctly detected as 40-wire connected
>> but this cable is short enough to still do transfers higher than UDMA33.
>
> Looks good to me - does need a Signed-off-by: line however
Wow! I have been running 80wire cable detection override on 40wire cables
for quite some time without any problem, but I never thought it to be legal
if the 40wire cable length is short enough.
How short does it have to be, and can't we have a kernel bootparm to override
the cable detection?
Thanks!
--
Al
> Wow! I have been running 80wire cable detection override on 40wire cables
> for quite some time without any problem, but I never thought it to be legal
> if the 40wire cable length is short enough.
Yes.
> How short does it have to be, and can't we have a kernel bootparm to override
> the cable detection?
For most users the goal should be to automate behaviour. It should just
work.
Alan Cox wrote:
> > Wow! I have been running 80wire cable detection override on 40wire
> > cables for quite some time without any problem, but I never thought it
> > to be legal if the 40wire cable length is short enough.
>
> Yes.
>
> > How short does it have to be, and can't we have a kernel bootparm to
> > override the cable detection?
>
> For most users the goal should be to automate behaviour. It should just
> work.
What's the max length of a 40wire cable to sustain 80wire cable
characteristics?
Thanks!
--
Al
Al Boldi wrote:
> Alan Cox wrote:
>>> Wow! I have been running 80wire cable detection override on 40wire
>>> cables for quite some time without any problem, but I never thought it
>>> to be legal if the 40wire cable length is short enough.
>> Yes.
>>
>>> How short does it have to be, and can't we have a kernel bootparm to
>>> override the cable detection?
>> For most users the goal should be to automate behaviour. It should just
>> work.
>
> What's the max length of a 40wire cable to sustain 80wire cable
> characteristics?
This is normally only the case on a laptop, where the cable is
essentially just a tiny stub between the motherboard and the drive. I
suspect this is something that the system manufacturer has to validate
works properly, more than any hard and fast limit.
For a normal desktop PC, it would be far better to just use an 80-wire
cable.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from [email protected]
Home Page: http://www.roberthancock.com/
On Aug 30 2007 16:54, Al Boldi wrote:
>
>What's the max length of a 40wire cable to sustain 80wire cable
>characteristics?
Hard to tell, since some (most?) laptops have sort of a backplane and there
might be no real cable you could see because it's all mainboard wire paths
already.
Jan
--
On Thu, Aug 30, 2007 at 09:38:23PM +0200, Jan Engelhardt wrote:
> Hard to tell, since some (most?) laptops have sort of a backplane and there
> might be no real cable you could see because it's all mainboard wire paths
> already.
Makes you wonder why the mainboard doesn't just pretend to be an 80 wire
cable if that is what it is compatible with. Seems like a design flaw
in the laptop to not do so.
--
Len Sorensen
On Aug 30 2007 15:47, Lennart Sorensen wrote:
>On Thu, Aug 30, 2007 at 09:38:23PM +0200, Jan Engelhardt wrote:
>> Hard to tell, since some (most?) laptops have sort of a backplane and there
>> might be no real cable you could see because it's all mainboard wire paths
>> already.
>
>Makes you wonder why the mainboard doesn't just pretend to be an 80 wire
>cable if that is what it is compatible with. Seems like a design flaw
>in the laptop to not do so.
Or lazyness on behalf the vendor. You know, some even don't fix their DSDT...
Jan
--
> What's the max length of a 40wire cable to sustain 80wire cable
> characteristics?
Depends on the materials and connector. The required electrical
characteristics for any cable are in the spec, and if you want to know
more you'll need to know a lot more than I do about transmission line
theory!
Hi!
Please CC me, as I'm currently not subscribed to this list, thx.
Another try :)
--
Greetings
Daniel Exner
On Friday 31 August 2007, Daniel Exner wrote:
> Hi!
>
> Please CC me, as I'm currently not subscribed to this list, thx.
applied but please inline patches instead of attaching them next time
(makes it much easier to review/apply them)