On 21 May 2015 at 16:04, Alexandre Courbot gnurou@gmail.com wrote:
On Thu, May 21, 2015 at 2:55 PM, Ben Skeggs skeggsb@gmail.com wrote:
On 21 May 2015 at 15:49, Alexandre Courbot gnurou@gmail.com wrote:
On Thu, May 21, 2015 at 1:48 PM, Ben Skeggs skeggsb@gmail.com wrote:
On 20 May 2015 at 15:56, Alexandre Courbot acourbot@nvidia.com wrote:
Add a module option allowing to enable staging/unstable APIs. This will allow us to experiment freely with experimental APIs for a while before setting them in stone.
Signed-off-by: Alexandre Courbot acourbot@nvidia.com
drm/nouveau/nouveau_drm.c | 18 ++++++++++++++++++ drm/nouveau/uapi/drm/nouveau_drm.h | 3 +++ 2 files changed, 21 insertions(+)
diff --git a/drm/nouveau/nouveau_drm.c b/drm/nouveau/nouveau_drm.c index 89049335b738..e4bd6ed51e73 100644 --- a/drm/nouveau/nouveau_drm.c +++ b/drm/nouveau/nouveau_drm.c @@ -75,6 +75,10 @@ MODULE_PARM_DESC(runpm, "disable (0), force enable (1), optimus only default (-1 int nouveau_runtime_pm = -1; module_param_named(runpm, nouveau_runtime_pm, int, 0400);
+MODULE_PARM_DESC(staging, "enable staging APIs"); +int nouveau_staging = 0; +module_param_named(staging, nouveau_staging, int, 0400);
static struct drm_driver driver_stub; static struct drm_driver driver_pci; static struct drm_driver driver_platform; @@ -895,6 +899,7 @@ nouveau_ioctls[] = { DRM_IOCTL_DEF_DRV(NOUVEAU_GEM_CPU_PREP, nouveau_gem_ioctl_cpu_prep, DRM_UNLOCKED|DRM_AUTH|DRM_RENDER_ALLOW), DRM_IOCTL_DEF_DRV(NOUVEAU_GEM_CPU_FINI, nouveau_gem_ioctl_cpu_fini, DRM_UNLOCKED|DRM_AUTH|DRM_RENDER_ALLOW), DRM_IOCTL_DEF_DRV(NOUVEAU_GEM_INFO, nouveau_gem_ioctl_info, DRM_UNLOCKED|DRM_AUTH|DRM_RENDER_ALLOW),
/* Staging ioctls */};
long @@ -1027,6 +1032,7 @@ static void nouveau_display_options(void) DRM_DEBUG_DRIVER("... runpm : %d\n", nouveau_runtime_pm); DRM_DEBUG_DRIVER("... vram_pushbuf : %d\n", nouveau_vram_pushbuf); DRM_DEBUG_DRIVER("... pstate : %d\n", nouveau_pstate);
DRM_DEBUG_DRIVER("... staging : %d\n", nouveau_staging);}
static const struct dev_pm_ops nouveau_pm_ops = { @@ -1088,6 +1094,18 @@ err_free: static int __init nouveau_drm_init(void) {
/* Do not register staging ioctsl if option not specified */if (!nouveau_staging) {unsigned i;/* This keeps us safe is no staging ioctls are defined */i = min(driver_stub.num_ioctls, DRM_NOUVEAU_STAGING_IOCTL);while (!nouveau_ioctls[i - 1].func)i--;driver_stub.num_ioctls = i;}Hey Alex,
I've got no specific objection. But I'm curious as to why you took this approach as opposed to just adding "if (!nouveau_staging) return -EINVAL;" directly in the experimental ioctls?
Mainly because we will likely forget to add this check (or to remove it) in some of the staging ioctls. The current solution doesn't require us to think about that - and the less things to think about, the better.
I think, in line with what's been done in other places, having module options per-api is perhaps a better choice too.
Do you mean that each experimental ioctl should have its own enable option? I don't mind going that way if you think it is preferable. And in that case my comment above is void.
That would be more preferable I think, and obvious as to what exactly you're enabling.
But actually I wonder if having these experimental ioctls enabled as compile options (either individually or as a whole) would not be better. Some experimental ioctls may require code in staging (like the PUSHBUF_2 ioctl that I would like to submit next), and I don't think it is desirable to force extra code or kernel options (in this case, CONFIG_STAGING) to Nouveau users who will not make use of them. I remember that we concluded in favor or module options on IRC, but in the light of this, wouldn't a config option be a less intrusive choice?
Right, but the whole point of this is to encourage the ioctls to not live there for too long, and progress to fully supported interfaces.
Definitely, but my concern is that doing this will make Nouveau depend on STAGING for at least short periods of time. Do we really want this?
I admit to having slightly misread your last paragraph. For cases such as thas, a config option that depends on STAGING *and* the kernel parameter should be used.
What is pushbuf2 doing that requires staging btw? You've linked me to patches previously, but I missed that.
Ben.