Hi Peter
On Wed, Jan 27, 2016 at 6:17 PM, Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote:
> The ACPI device definition block is not right.
> I mean, the whole point of ACPI is to _define_ the h/w so the OS
> doesn't h/w probe.
>
> Is this in your firmware that you can update?
>
Unfortunately, it is part of the BIOS blob that I am not in control of.
>
>> I cannot find anything that makes it differentiable form a standard
>> 16550A, but ACPI is definately not my mother tonge :)
>>
>> Device (UAR1)
>> {
>> Name (_HID, EisaId ("PNP0501") /* 16550A-compatible COM Serial Port */) // _HID: Hardware ID
>
> Instead of using an _HID of PNP0501, this device definition should be
> using a Fintek-specific _HID (Fintek has an assigned PNP prefix of "FIT").
>
> Then it could *also* have a _CID of PNP0501, which allows the OS to
> "fallback" to generic uart support in the absence of a "FITxxxx" driver.
I see, but even if I was in control of the ACPI table, which FITxxx
string should I use? The documentation from the chip does not mention
any.
If I chose one myself there is no warrantee that the rest of the world
would follow my decision, resulting in a driver that can be used
exclusively on my board :S.
The approach from this patch is similar to the parport_pc
./drivers/parport/parport_pc.c ->
static void __init parport_pc_find_ports(int autoirq, int autodma)
{
int count = 0, err;
#ifdef CONFIG_PARPORT_PC_SUPERIO
detect_and_report_it87();
detect_and_report_winbond();
detect_and_report_smsc();
#endif
static void detect_and_report_winbond(void)
{
if (verbose_probing)
printk(KERN_DEBUG "Winbond Super-IO detection, now testing ports
3F0,370,250,4E,2E ...\n");
winbond_check(0x3f0, 0x87);
winbond_check(0x370, 0x87);
winbond_check(0x2e , 0x87);
winbond_check(0x4e , 0x87);
winbond_check(0x3f0, 0x86);
winbond_check2(0x250, 0x88);
winbond_check2(0x250, 0x89);
}
Here they probe all those io ports, including 0x4e and 0x2e like in my chip.
If I have to guess I would say that all the fintek serial ports on the
field are declared only as PNP0501, not only my board :S
Thanks!
--
Ricardo Ribalda
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