Hi Stephen, On Thu, Mar 09, 2023 at 03:31:15PM -0800, Stephen Boyd wrote: > Quoting Maxime Ripard (2023-03-03 06:35:28) > > On Fri, Mar 03, 2023 at 03:15:31PM +0800, David Gow wrote: > > > > > > DRM has a similar thing already (albeit with a root_device, which is > > > more common with KUnit tests generally): > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/drm/drm_kunit_helpers.h > > > > > > But that's reasonably drm-specific, so it makes sense that it lives > > > with DRM stuff. platform_device is a bit more generic. > > > > I'd be very happy to get something from the core to address the same > > thing. > > > > I think the main thing we needed that isn't covered by this patch is we > > wanted the device to be bound to its driver, so with probe being called > > before calling the test (see 57a84a97bbda). > > Can you clarify? This patch makes a poor attempt at waiting for the > platform driver to bind, but in reality it may not be bound by the time > the driver register function returns. The issue was that devm will only clean up the resources if the device was bound to a driver so we were exhausting resources when running dozens of test in a sequence. The way I solved it for vc4 was to create a dumb platform driver with a waitqueue, and wait for probe to be called. I think we could make it more generic by allowing a pointer to a probe function and calling it into our own probe implementation. What do you think? Maxime
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