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

[Hans de Goede]

Hi,

On 24-07-15 04:32, Ben Skeggs 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?

I've grabbed 304.125

> You *might* need to use "modprobe
> nvidia NVreg_EnableMSI=1", because at some point NVIDIA didn't use it
> by default anywhere.

You're right I needed to specify NVreg_EnableMSI=1, with that set
/proc/interrupts shows that MSI is used.

Here is an of running glxgears with the binary driver using msi interrupts mmiotrace:

https://fedorapeople.org/~jwrdegoede/nvidia-bin-nv46-msi-on-glxgears.mmiotrace.gz

AFAIK there are some nouveau tools to parse this a bit, right ? I'm going
to call it a day for today, if you can give me some pointers what to do with the
mmiotrace to find a potential fix for the msi issues, that would be appreciated.


BTW I had to build my own kernel with mmiotrace enabled in Kconfig, as this
is disabled in the Fedora kernels by default. Do you know if there is a good
reason to have this disabled by default, or should I ask the Fedora
kernel maintainers to enable it by default ?


Slightly offtopic:

I decided to be bold and try gnome-shell on the nv46 with msi disabled,
which sofar was a guaranteed way to freeze the system, and it now works
somewhat (latest kernel, ddx and mesa). I see something which shows
horizontal lines which are small parts from my desktop background, and
things change significantly when I switch to the overview mode.

But other then that the display is completely wrong, it looks a bit
like a framebuffer pitch problem, but then different. I think it
is likely some tiling problem or some such.

Note that metacity + glxgears works, this only shows with
gnome-shell, any hints where to start looking wrt debugging this?

Or should I first try to run piglet and see if some tests there
point out the culprit?


Regards,

Hans



>
> Thanks,
> Ben.
>
>> BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=90435
>> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
>> ---
>>   drivers/gpu/drm/nouveau/nvkm/engine/device/nv40.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/nv40.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/nv40.c
>> index c630136..b4ad791 100644
>> --- a/drivers/gpu/drm/nouveau/nvkm/engine/device/nv40.c
>> +++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/nv40.c
>> @@ -265,7 +265,7 @@ nv40_identify(struct nvkm_device *device)
>>                  device->oclass[NVDEV_SUBDEV_CLK    ] = &nv40_clk_oclass;
>>                  device->oclass[NVDEV_SUBDEV_THERM  ] = &nv40_therm_oclass;
>>                  device->oclass[NVDEV_SUBDEV_DEVINIT] =  nv1a_devinit_oclass;
>> -               device->oclass[NVDEV_SUBDEV_MC     ] =  nv44_mc_oclass;
>> +               device->oclass[NVDEV_SUBDEV_MC     ] =  nv4c_mc_oclass;
>>                  device->oclass[NVDEV_SUBDEV_BUS    ] =  nv31_bus_oclass;
>>                  device->oclass[NVDEV_SUBDEV_TIMER  ] = &nv04_timer_oclass;
>>                  device->oclass[NVDEV_SUBDEV_FB     ] =  nv46_fb_oclass;
>> --
>> 2.4.3
>>
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