Re: nativedisk not working in 2.0.4

[Brian J. Murrell]

On Fri, 2020-12-04 at 11:08 +0300, Andrei Borzenkov wrote:
> 
> There are at least two issues here
> 
> 1. You automatically presume that loaded drivers are capable to work
> with your hardware.

Without having any reason to believe otherwise, as I might have now,
sure.  I'm an optimist.

> 2. Native drivers were never designed to be freely interchangeable
> with
> platform drivers. They were intended to be used on bare metal
> platforms,
> where GRUB is basically loaded by firmware *instead of* BIOS and has
> full control over hardware.

So people on common "PC" platforms are going to have little chance of
using, say, USB serial ports then.  Pity, given so many machines ship
without them any more.

>  When you first boot using conventional BIOS,
> firmware installs drivers to handle disk/USB/... etc IO. When you
> tell
> grub to switch to native drivers, BIOS drivers remain active. So now
> you
> have *two* independent sets of drivers that attempt to "drive" the
> same
> hardware. Chaos follows.

Understandable.  But I am also not a boot/bios/firmware/etc. guru, so
my understanding of these things is only ancillary.  I suspect the same
goes for a lot of people.  It might prove useful to document these
kinds of details somewhere.

> In some cases it may be possible to make it work (e.g. USB has
> special
> protocol that allows OS - or GRUB in this case - to inform BIOS that
> OS
> takes control over device). In other cases - like AHCI controller - I
> am
> not sure it is even possible.

Heh.  My next step was going to be to abandon SD-Card (usbms) and use a
SATA disk in the machine.  But you are suggesting that that is likely
even less likely to work?

FWIW, with a SATA disk in the machine, nativedisk hangs grub in the
same way as usbms does.  :-(

This really is all a pity.  As useful as a serial console is with, say,
Linux, having it available during bootloader time is invaluable.

Cheers,
b.

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