On 6 February 2017 at 19:57, Rob Clark <robdclark@xxxxxxxxx> wrote:
> On Mon, Feb 6, 2017 at 2:20 PM, Emil Velikov <emil.l.velikov@xxxxxxxxx> wrote:
>> Hi Jordan,
>>
>> On 6 February 2017 at 17:39, Jordan Crouse <jcrouse@xxxxxxxxxxxxxx> wrote:
>>> Modify the 'pad' member of struct drm_msm_gem_info to 'hint'. If the
>>> user sets 'hint' to non-zero it means that they want a IOVA for the
>>> GEM object instead of a mmap() offset. Return the iova in the 'offset'
>>> member.
>>>
>>> Signed-off-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
>>> ---
>>> drivers/gpu/drm/msm/msm_drv.c | 29 +++++++++++++++++++++++++----
>>> include/uapi/drm/msm_drm.h | 4 ++--
>>> 2 files changed, 27 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
>>> index e29bb66..1e4e022 100644
>>> --- a/drivers/gpu/drm/msm/msm_drv.c
>>> +++ b/drivers/gpu/drm/msm/msm_drv.c
>>> @@ -677,6 +677,17 @@ static int msm_ioctl_gem_cpu_fini(struct drm_device *dev, void *data,
>>> return ret;
>>> }
>>>
>>> +static int msm_ioctl_gem_info_iova(struct drm_device *dev,
>>> + struct drm_gem_object *obj, uint64_t *iova)
>>> +{
>>> + struct msm_drm_private *priv = dev->dev_private;
>>> +
>>> + if (!priv->gpu)
>>> + return -EINVAL;
>>> +
>> Not too familiar with msm so perhaps a silly question: how can we trigger this ?
>
> if gpu has not loaded (for example, missing firmware, or kernel does
> not have iommu, etc)
>
Thanks Rob. I was under the impression that in such cases the driver
will/should fail to load.
>>> + __u64 offset; /* out, mmap() offset if hint is 0, iova if 1 */
>> Other drivers have used anonymous unions to improve the naming, in
>> such situations.
>>
>> struct drm_msm_gem_info {
>> __u32 handle; /* in */
>> __u32 hint; /* in */
>> union { /* out */
>> __u64 offset; /* offset if hint is FOO */
>> __u64 iova; /* iova if hint is BAR */
>> };
>> };
>
> is anon union legit for uabi? I was under the impression that for
> some reason it was not. But I could be wrong.
>
Haven't seen any wording against it and we do have a few instances in
DRM UABI land.
Either way it was just an idea.
Regards,
Emil
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