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SubjectRe: new PCI quirk for Toshiba Satellite?
Jesse Barnes wrote:
> Stefan, is a PCI quirk addition possible or do we have to use
> dmi_check_system in the ohci driver itself (since we have to reprogram
> the cache line size in addition to the other registers)?

I am not familiar with the PCI subsystem, thus cannot advise how to
handle it best nor wanted to post a patch myself (yet).

[...]
>> .callback = ohci1394_toshiba_reprogram_config,
>> .ident = "Toshiba PSM4 based laptop",
>> .matches = {
>> DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
>> DMI_MATCH(DMI_PRODUCT_VERSION, "PSM4"),
>> },
>> .driver_data = &tosh_data;

It seems to me, using the .callback and .driver_data doesn't make it
cleaner and leaner.

> But then what about the dev->current_state = 4? Is that necessary?

It is necessary; at least if the workaround resides in ohci1394.
Otherwise the controller won't come back after a suspend/ resume cycle.
(See Rob's post from February,
http://marc.theaimsgroup.com/?m=110786495210243 ) Maybe there is another
way to do that if the workaround was moved to pci/quirks.c.

[...]
> + if (toshiba) {
> + dev->current_state = 4;
> + pci_read_config_word(dev, PCI_CACHE_LINE_SIZE, &toshiba_data);
> + }
> +
> if (pci_enable_device(dev))
> FAIL(-ENXIO, "Failed to enable OHCI hardware");
> pci_set_master(dev);
>
> + if (toshiba) {
> + mdelay(10);
> + pci_write_config_word(dev, PCI_CACHE_LINE_SIZE, toshiba_data);
[...]

pci_set_master(dev) can be moved below the second part of the Toshiba
workaround. That means AFAIU, the 2nd part of the Toshiba workaround can
be moved out of ohci1394 into pci_fixup_device() which is called from
pci_enable_device(), to be called as a DECLARE_PCI_FIXUP_ENABLE hook.

The first part of the workaround, i.e. caching the cache line size, for
example by means of a static variable, would have to go into an
_FIXUP_EARLY, _FIXUP_HEADER, or _FIXUP_FINAL hook. I am not sure yet
about which type of hook to use.

Furthermore, everything which belongs to the workaround should IMO be
enclosed by #ifdef SOME_SENSIBLE_MACRO. This avoids kernel bloat for any
target which is surely not a Toshiba laptop. Rob used an #if
defined(__i386__).
--
Stefan Richter
-=====-=-=-= =-=- =-=-=
http://arcgraph.de/sr/
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