On Wed, Jun 26, 2024 at 12:55:39PM GMT, Tomi Valkeinen wrote: > On 26/06/2024 11:49, Maxime Ripard wrote: > > Hi, > > > > On Wed, Jun 19, 2024 at 12:07:48PM GMT, Tomi Valkeinen wrote: > > > From: Tomi Valkeinen <tomi.valkeinen+renesas@xxxxxxxxxxxxxxxx> > > > > > > When a bridge driver uses devm_mipi_dsi_device_register_full() or > > > devm_mipi_dsi_attach(), the resource management is moved to devres, > > > which releases the resource automatically when the bridge driver is > > > unbound. > > > > > > However, if the DSI host goes away first, the host unregistration code > > > will automatically detach and unregister any DSI peripherals, without > > > notifying the devres about it. So when the bridge driver later is > > > unbound, the resources are released a second time, leading to crash. > > > > That's super surprising. mipi_dsi_device_unregister calls > > device_unregister, which calls device_del, which in turn calls > > devres_release_all. > > Hmm, right. > > > If that doesn't work like that, then it's what needs to be fixed, and > > not worked around in the MIPI-DSI bus. > > Well, something causes a crash for both the device register/unregister case > and the attach/detach case, and the call stacks and debug prints showed a > double unregister/detach... > > I need to dig up the board and check again why the devres_release_all() in > device_del() doesn't solve this. But I can probably only get back to this in > August, so it's perhaps best to ignore this patch for now. > > However, the attach/detach case is still valid? I see no devres calls in the > detach paths. I'm not sure what you mean by the attach/detach case. Do you expect device resources allocated in attach to be freed when detach run? Maxime
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