Re: [REGRESSION] GM20B probe fails after commit 2541626cfb79

[Ben Skeggs <skeggsb@gmail.com>]

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On Fri, 20 Jan 2023 at 21:37, Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt> wrote:
>
> On Wed, Jan 18, 2023 at 11:28:49AM +1000, Ben Skeggs wrote:
> > On Mon, 16 Jan 2023 at 22:27, Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt> wrote:
> > > On Mon, Jan 16, 2023 at 07:45:05AM +1000, David Airlie wrote:
> > > > As a quick check can you try changing
> > > >
> > > > drivers/gpu/drm/nouveau/nvkm/core/firmware.c:nvkm_firmware_mem_target
> > > > from NVKM_MEM_TARGET_HOST to NVKM_MEM_TARGET_NCOH ?
>
> > In addition to Dave's change, can you try changing the
> > nvkm_falcon_load_dmem() call in gm20b_pmu_init() to:
> >
> > nvkm_falcon_pio_wr(falcon, (u8 *)&args, 0, 0, DMEM, addr_args,
> > sizeof(args), 0, false);
>
> Hello!
>
> Chiming in just to say that with this change I see the same as Nicolas
> except that the init message size is 255 instead of 0:
>
> [    2.196934] nouveau 57000000.gpu: pmu: unexpected init message size 255 vs 42
I've attached an entirely untested patch (to go on top of the other
hacks/fixes so far), that will hopefully get us a little further.

Would be great if you guys could test it out for me.

Thanks,
Ben.

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diff --git a/drivers/gpu/drm/nouveau/nvkm/falcon/gm200.c b/drivers/gpu/drm/nouveau/nvkm/falcon/gm200.c
index 393ade9f7e6c..b7da3ab44c27 100644
--- a/drivers/gpu/drm/nouveau/nvkm/falcon/gm200.c
+++ b/drivers/gpu/drm/nouveau/nvkm/falcon/gm200.c
@@ -48,6 +48,16 @@ gm200_flcn_pio_dmem_rd(struct nvkm_falcon *falcon, u8 port, const u8 *img, int l
 		img += 4;
 		len -= 4;
 	}
+
+	/* Sigh.  Tegra PMU FW's init message... */
+	if (len) {
+		u32 data = nvkm_falcon_rd32(falcon, 0x1c4 + (port * 8));
+
+		while (len--) {
+			*(u8 *)img++ = data & 0xff;
+			data >>= 8;
+		}
+	}
 }
 
 static void
@@ -64,6 +74,8 @@ gm200_flcn_pio_dmem_wr(struct nvkm_falcon *falcon, u8 port, const u8 *img, int l
 		img += 4;
 		len -= 4;
 	}
+
+	WARN_ON(len);
 }
 
 static void
@@ -74,7 +86,7 @@ gm200_flcn_pio_dmem_wr_init(struct nvkm_falcon *falcon, u8 port, bool sec, u32 d
 
 const struct nvkm_falcon_func_pio
 gm200_flcn_dmem_pio = {
-	.min = 4,
+	.min = 1,
 	.max = 0x100,
 	.wr_init = gm200_flcn_pio_dmem_wr_init,
 	.wr = gm200_flcn_pio_dmem_wr,