Re: Device driver chip architcture dependencies

[Benjamin Tseng <tseng.ben@xxxxxxxxx>]

Thank you, Vitus. That was very interesting. Quick followup question.
I took a look at /drivers in the Linux kernel and did a quick grep search
for files containing "#ifdef __arm__" and only a handful of files came up.
Is it fair to read into this that it means most drivers (assuming the
devices operate with the same buses) are 100% compatible with Linux-on-ARM
and need only a simple re-compile? Or is it that these device drivers have
never been tested on systems running ARM architecture and so nobody has ever
made the necessary modifications?

--Ben

On Sun, Mar 8, 2009 at 3:39 PM, Vitus Jensen <vjensen@xxxxxx> wrote:

> Am Sun, 08 Mar 2009 13:11:47 -0700 schrieb Benjamin Tseng:
>
> > Apologies if this is an incredibly newbie question as I have never
> > programmed at the kernel/device driver level (and am new to this mailing
> > list), but I'm very interested in the new flavors of netbooks which are
> > coming out which will be powered by new ARM chips (e.g. snapdragon,
> > sparrow, etc), and wanted to ask the experts if the device drivers that
> > I currently have working on my x86-Linux notebook work with the new
> > ARM-Linux netbooks?
>
> This depends.  If the driver is included in the linux kernel it may be as
> simple as a recompile.  But are you sure those device you need drivers
> for are really the same?  Your current laptop may contain a device
> connected to the PCI bus, will those netbooks contain such a bus?
> Perhaps it will be connected through USB, I2C, SSP, SDIO instead?
> Different code to write...
>
> > For my curiosity's sake, I'm also wondering if getting drivers to work
> > across multiple architectures requires significant
> > re-compiling/re-coding work -- e.g. will HP/Linux community decide its
> > not worth the hassle of re-coding drivers to work on ARM-Linux?
>
> If the driver has been accepted by the linux kernel guys it's probably
> done right and doesn't need recoding.  If it's an indepedent afford you
> don't know.  And if it's binary only (like nvidea's and ATI's drivers)
> you have to use a different driver (or beg those companies for a driver).
>
> Bye,
>   Vitus
>
> --
> BUFFERS=7 FILES=5 2nd down 4th quarter 5 yards to go
>
> Vitus Jensen, Hannover, Germany, Earth, Milky Way, Universe (current)
>
>
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