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Commit 18acc6d8 authored by Martin Peres's avatar Martin Peres Committed by Ben Skeggs
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drm/nouveau/bios: fetch the vbios from PROM using only aligned 32-bit accesses 



Other kind of accesses are unreliable on Kepler cards. As advised by NVIDIA,
let's only use 32-bit accesses to fetch the vbios from PROM.

This fixes vbios fetching on my nve7 which failed in certain specific
conditions.

I suggest we Cc stable, for all kernels they still maintain after the big
rewrite.

Suggested-by: default avatarChristian Zander <czander@nvidia.com>
Signed-off-by: default avatarMartin Peres <martin.peres@free.fr>
Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
parent 0e994d64

drivers/gpu/drm/nouveau/core/subdev/bios/base.c

+19 −14
Original line number Diff line number Diff line
@@ -157,6 +157,10 @@ nouveau_bios_shadow_prom(struct nouveau_bios *bios) 
		pcireg = 0x001850;

	access = nv_mask(bios, pcireg, 0x00000001, 0x00000000);



	/* WARNING: PROM accesses should always be 32-bits aligned. Other

	 * accesses work on most chipset but do not on Kepler chipsets

	 */



	/* bail if no rom signature, with a workaround for a PROM reading

	 * issue on some chipsets.  the first read after a period of

	 * inactivity returns the wrong result, so retry the first header
@@ -164,31 +168,32 @@ nouveau_bios_shadow_prom(struct nouveau_bios *bios) 
	 */

	i = 16;

	do {

		if (nv_rd08(bios, 0x300000) == 0x55)

		if ((nv_rd32(bios, 0x300000) & 0xffff) == 0xaa55)

			break;

	} while (i--);



	if (!i || nv_rd08(bios, 0x300001) != 0xaa)

		goto out;



	/* additional check (see note below) - read PCI record header */

	pcir = nv_rd08(bios, 0x300018) |

	       nv_rd08(bios, 0x300019) << 8;

	if (nv_rd08(bios, 0x300000 + pcir) != 'P' ||

	    nv_rd08(bios, 0x300001 + pcir) != 'C' ||

	    nv_rd08(bios, 0x300002 + pcir) != 'I' ||

	    nv_rd08(bios, 0x300003 + pcir) != 'R')

	if (!i)

		goto out;



	/* read entire bios image to system memory */

	bios->size = nv_rd08(bios, 0x300002) * 512;

	bios->size = ((nv_rd32(bios, 0x300000) >> 16) & 0xff) * 512;

	if (!bios->size)

		goto out;



	bios->data = kmalloc(bios->size, GFP_KERNEL);

	if (bios->data) {

		for (i = 0; i < bios->size; i++)

			nv_wo08(bios, i, nv_rd08(bios, 0x300000 + i));

		for (i = 0; i < bios->size; i+=4)

			nv_wo32(bios, i, nv_rd32(bios, 0x300000 + i));

	}



	/* check the PCI record header */

	pcir = nv_ro16(bios, 0x0018);

	if (bios->data[pcir + 0] != 'P' ||

	    bios->data[pcir + 1] != 'C' ||

	    bios->data[pcir + 2] != 'I' ||

	    bios->data[pcir + 3] != 'R') {

		bios->size = 0;

		kfree(bios->data);

	}



out: