On Wed, Jul 15, 2020 at 11:37 AM Jonathan Marek <jonathan@xxxxxxxx> wrote:
>
> On 7/15/20 2:29 PM, Rob Clark wrote:
> > From: Rob Clark <robdclark@xxxxxxxxxxxx>
> >
> > If there is no interconnect-names, but there is an interconnects
> > property, then of_icc_get(dev, "gfx-mem"); would return an error
> > rather than NULL.
> >
> > Also, if there is no interconnect-names property, there will never
> > be a ocmem path. But of_icc_get(dev, "ocmem") would return -EINVAL
> > instead of -ENODATA. Just don't bother trying in this case.
> >
> > Fixes: 8e29fb37b301 ("drm/msm: handle for EPROBE_DEFER for of_icc_get")
> > Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/msm/adreno/adreno_gpu.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > index 0527e85184e1..c4ac998b90c8 100644
> > --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > @@ -979,6 +979,7 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
> > struct adreno_platform_config *config = dev->platform_data;
> > struct msm_gpu_config adreno_gpu_config = { 0 };
> > struct msm_gpu *gpu = &adreno_gpu->base;
> > + bool has_interconnect_names = true;
> > int ret;
> >
> > adreno_gpu->funcs = funcs;
> > @@ -1005,12 +1006,13 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
> >
> > /* Check for an interconnect path for the bus */
> > gpu->icc_path = of_icc_get(dev, "gfx-mem");
> > - if (!gpu->icc_path) {
> > + if (IS_ERR_OR_NULL(gpu->icc_path)) {
> > /*
> > * Keep compatbility with device trees that don't have an
> > * interconnect-names property.
> > */
> > gpu->icc_path = of_icc_get(dev, NULL);
>
> This is misleading because if it gets a EPROBE_DEFER error (or any other
> error), it will hit this path. Maybe there's a specific error you can
> check for instead to identify the "no-interconnect-names" case?
good point, we should probably instead just explicitly check with
of_find_property("interconnect-names")
fwiw, of_icc_get() returns:
- NULL if icc disabled, or no "interconnects" property
- -EINVAL if name!=NULL and no "interconnect-names"
- and looks like -ENODATA if name!=NULL but no match in
interconnect-names
The specific error returns aren't really called out in the API comment
block, so not really sure how much we should rely on them not being
implementation details.
BR,
-R
> Also don't think its a good idea to be calling of_icc_get(dev, NULL)
> again when there's a EPROBE_DEFER, the interconnect driver could come up
> between the two calls
>
> > + has_interconnect_names = false;
> > }
> > if (IS_ERR(gpu->icc_path)) {
> > ret = PTR_ERR(gpu->icc_path);
> > @@ -1018,7 +1020,9 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
> > return ret;
> > }
> >
> > - gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
> > + if (has_interconnect_names)
> > + gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
> > +
> > if (IS_ERR(gpu->ocmem_icc_path)) {
> > ret = PTR_ERR(gpu->ocmem_icc_path);
> > gpu->ocmem_icc_path = NULL;
> >
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