drm/nouveau: Don't clear AGPCMD completely on INIT_RESET.
authorFrancisco Jerez <currojerez@riseup.net>
Thu, 17 Jun 2010 10:42:14 +0000 (12:42 +0200)
committerBen Skeggs <bskeggs@redhat.com>
Tue, 13 Jul 2010 00:13:04 +0000 (10:13 +1000)
commit190a43783f2c43186180c827444d4eac901b4bcf
tree9eb197e45a1991e891c5d56e8b938c515d0a3787
parent2fa67f12e71d7f8adade7c4e6bb839156dea2365
drm/nouveau: Don't clear AGPCMD completely on INIT_RESET.

We just need to clear the SBA and ENABLE bits to reset the AGP
controller: If the AGP bridge was configured to use "fast writes",
clearing the FW bit would break the subsequent MMIO writes and
eventually end with a lockup.

Note that all the BIOSes I've seen do the same as we did (it works for
them because they don't use MMIO), OTOH the blob leaves FW untouched.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
drivers/gpu/drm/nouveau/nouveau_bios.c