[Nouveau] [PATCH] nouveau: nv46: Change mc subdev oclass from nv44 to nv4c

[Ben Skeggs]

On 24 July 2015 at 12:39, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Thu, Jul 23, 2015 at 10:32 PM, Ben Skeggs <skeggsb at gmail.com> wrote:
>> On 24 July 2015 at 01:20, Hans de Goede <hdegoede at redhat.com> wrote:
>>> MSI interrupts appear to not work for nv46 based cards. Change the mc
>>> subdev oclass for these cards from nv44 to nv4c, the nv4c mc code is
>>> identical to the nv44 mc code except that it does not use msi
>>> (it does not define a msi_rearm callback).
>> I'm fine with this, but it'd be nice to check that the binary driver
>> doesn't/can't use MSI on these too (there might be an alternate method
>> we need to use).
>>
>> Would you be able to grab the latest proprietary driver that works on
>> nv4x, and do a mmiotrace of it?  You *might* need to use "modprobe
>> nvidia NVreg_EnableMSI=1", because at some point NVIDIA didn't use it
>> by default anywhere.
>
> AFAIK the blob never used MSI on nv4x. Perhaps we should have just
> left it alone...
They have support for it, it was just never on by default (for any
chipset) during the supported lifetime of nv4x.