[lkml]   [2008]   [Mar]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: ultrastor.c is a bit-rot
On Mon, 2008-03-17 at 16:59 +0200, Boaz Harrosh wrote:
> Inspecting ultrastor.c it is clear to me that this was never used for
> a loooooooooong time. Not since a PC has more then 2^24 bit of memory.
> Let me explain below.
> Now I'm not saying it should be fixed. I'm saying that it should be dumped
> in the account that it is not used by any one and that it does not work.
> Why it never worked?
> ~~~~~~~~~~~~~~~~~~~~~
> The driver's header says it supports 3 cards
> * 14F - ISA first-party DMA HA with floppy support and WD1003 emulation.
> * 24F - EISA Bus Master HA with floppy support and WD1003 emulation.
> * 34F - VL-Bus Bus Master HA with floppy support (no WD1003 emulation).
> But Kconfig only specifies ISA. I'm not sure what a VL-Bus is.

VL is vesa local ... it was an ISA like graphics bus that was fast and
could reach > 16MB.

> now the driver defines a static array of structures like this:
> struct {
> ...
> struct mscp mscp[ULTRASTOR_MAX_CMDS];
> } config = {0};
> and allocates a struct mscp in .queuecommand like this:
> my_mscp = &config.mscp[mscp_index];
> it will go on preparing this my_mscp structure including stuffing
> some mapped pointers. Lets put that aside for now.
> At the very end it will pass this my_mscp structure to the card's
> firmware like this:
> /* Store pointer in OGM address bytes */
> outl(isa_virt_to_bus(my_mscp), config.ogm_address);
> Now this is one hell of a smart ISA card. But putting this aside.
> if the machine has more then 2^24 of memory. Then this will never
> work, right? or I'm missing it completely?

It will definitely work for EISA and VL bus. I think if you analyse the
placement of kernel data segments for compiled in drivers, it might also
work for ISA too, since I think the pfn will be low enough. It should
fail as a module not just because the area will be out of range for ISA,
but also because the module data segment is in vmalloc space, so the
virt_to_bus assumptions of contiguity could be violated.


 \ /
  Last update: 2008-03-17 16:25    [W:0.076 / U:0.408 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site