[ Upstream commit 517b91f4cde3043d77b2178548473e8545ef07cb ]

[What]
readptr read always returns zero, since most likely
these blocks are either power or clock gated.

[How]
fetch rptr after amdgpu_ring_alloc() which informs
the power management code that the block is about to be
used and hence the gating is turned off.
Signed-off-by: NLouis Li <Ching-shih.Li@amd.com>
Signed-off-by: NShirish S <shirish.s@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>