On Tue, Jul 14, 2020 at 06:55:30PM +0530, Akhil P Oommen wrote:
On targets where GMU is available, GMU takes over the ownership of GX GDSC during its initialization. So, take a refcount on the GX PD on behalf of GMU before we initialize it. This makes sure that nobody can collapse the GX GDSC once GMU owns the GX GDSC. This patch fixes some weird failures during GPU wake up during system resume.
The change looks fine but this explanation is confusing. When I read it I thought "oh, man, we weren't taking a reference to the GX PD during resume???" but that's not really the case. We *are* taking a reference, just not soon enough to avoid possible issues. It would be helpful if you reworded this to explain that you are moving the reference and perhaps to shine a bit more light on what the "weird" failures are.
Jordan
Signed-off-by: Akhil P Oommen akhilpo@codeaurora.org
drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c index a6f43ff..5b2df7d 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c @@ -873,10 +873,19 @@ int a6xx_gmu_resume(struct a6xx_gpu *a6xx_gpu) /* Turn on the resources */ pm_runtime_get_sync(gmu->dev);
- /*
* "enable" the GX power domain which won't actually do anything but it* will make sure that the refcounting is correct in case we need to* bring down the GX after a GMU failure*/- if (!IS_ERR_OR_NULL(gmu->gxpd))
pm_runtime_get_sync(gmu->gxpd);- /* Use a known rate to bring up the GMU */ clk_set_rate(gmu->core_clk, 200000000); ret = clk_bulk_prepare_enable(gmu->nr_clocks, gmu->clocks); if (ret) {
pm_runtime_put(gmu->gxpd);@@ -919,19 +928,12 @@ int a6xx_gmu_resume(struct a6xx_gpu *a6xx_gpu) /* Set the GPU to the current freq */ a6xx_gmu_set_initial_freq(gpu, gmu);
- /*
* "enable" the GX power domain which won't actually do anything but it* will make sure that the refcounting is correct in case we need to* bring down the GX after a GMU failure*/- if (!IS_ERR_OR_NULL(gmu->gxpd))
pm_runtime_get(gmu->gxpd);out: /* On failure, shut down the GMU to leave it in a good state */ if (ret) { disable_irq(gmu->gmu_irq); a6xx_rpmh_stop(gmu);
pm_runtime_put(gmu->gxpd);-- 2.7.4