Re: [Patch] USB hot-plugging support - usb branch

[Aleš Nesrsta]

Hi Vladimir,

Vladimir 'φ-coder/phcoder' Serbinenko wrote:
> > ...
> "statically" allocated EDs:
> >   -- number of EDs could be increased in ohci.c
> >   -- de-allocation of EDs should be added in ohci.c
> >
> >   
> You can have at most 255 devices on one controller. The easiest way is
> to allocate enough EDs for 255 devices

Yes, it is one of possible and simplest ways... In first try we can
increase number of EDs to approx. 255 + 1 control and 2*255 bulk EDs per
OHCI/UHCI controller. (We need one control ED and two bulk EDs per one
mass storage device plus one control zero ED for new connected device.)
I.e. currently we can simply change in ohci.c:
#define GRUB_OHCI_CTRL_EDS 256
#define GRUB_OHCI_BULK_EDS 510
and it should be enough...

But it will be better to finally implement also some ED de-allocating in
OHCI. I want to try to implement device-port information into usbdevice
structure and together with it add de-allocating of OHCI EDs - see
below.

> ...
> > There is missing handling of disconnected devices. For this we will
> need
> > to know on which port which device is attached - it is currently not
> > known
> But it can be easily stored in usbdevice structure.

I have similar idea, do you mean this structure ?

usb.h: struct grub_usb_device

(I am thinking how to simply implement recursive structure of USB bus -
root hub, hubs, devices on hubs at any level... Exists some similar
problems/structures somewhere in GRUB (to use the same or similar
implementation or, at least, to be inspired) ?)

But as I wrote in another today's e-mail to jonatan perry, I will
probably too busy in next weeks/months, so it may take some longer
time... ( BTW - What do you mean about EHCI driver and its priority in
GRUB development ? But it is probably theme for another mail thread...)

Regards
Ales