Re: Driver H/W init delay

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Thank you for usuful advices.

>
>  Things like getting monitor information through DDC take
>a long time.  Also, because clocks are being set there are
>PLL settling times that need to be observed least you mess
>things up by touching the hardware before the PLLs lock.
>

I have heard about this issue, but, in my env, doing DDC probe is
very fast. It is done instantaneously.
Is DDC really a cause?



>
>  It may be that particular drivers have unnecessary waits here
>and there, but you really have to address them one by one,
>profiling to find the wait and then investigating whether or
>not it's really necessary.
>

Then, the VESA driver of current XFree86 has unnecessary waits?
If so, I will try to get rid of. But, as far as I have glanced
the code, it just does call a VESA BIOS and it is all it does.
So, even there are unnecessary waits, they seems to be in a BIOS
code, I suppose.



>
>  I have worked on systems with boot times times on the order of
>a few seconds but these weren't trying to access VESA bios services
>or probing monitors through DDC.  If you remove stuff like that, the
>boot times will probably be dominated by IDE probing, but then
>you end up having to hardcode things like monitor EDIDs that
>the driver would usually try to probe.
>

Well, in MACH BOOT, it is possible to hard-code IDE params,
because most PCs has same param. But not possible to hard-code
DDC (EDID or...) because there are so many kind of monitor.
Any idea?


            --- Okajima, Jun. Tokyo, Japan.
                http://www.digitalinfra.co.jp/
                http://www.machboot.com/







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