On 29/02/16 10:14, Jon Hunter wrote: > > On 29/02/16 07:15, Thierry Reding wrote: >> * PGP Signed by an unknown key >> >> On Fri, Feb 26, 2016 at 03:48:37PM +0000, Jon Hunter wrote: >>> The genpd framework allows users to add power-domains via the >>> pm_genpd_init() function, however, there is no corresponding function >>> to remove a power-domain. For most devices this may be fine as the power >>> domains are never removed, however, for devices that wish to populate >>> the power-domains from within a driver, having the ability to remove a >>> power domain if the probing of the device fails or the driver is unloaded >>> is necessary. Therefore, add a function to remove a power-domain. Please >>> note that the power domain can only be removed if there are no devices >>> using the power-domain and it is not linked to another domain. >> >> So I guess this introduces a problem not uncommon to other types of >> resources. If you remove the driver, even if you fail ->remove() the >> module may still go away along with any code associated with it. So >> even if the PM domains can't be removed, you can't prevent the module >> from going away. That could be somewhat mitigated if we were holding a >> module reference count, because then the only way to unload the driver >> would be via sysfs (we could prevent that too, which might be the best >> way to do this today). >> >> There is work underway to solve this generically, Rafael was working on >> this, so I'm not sure we need to add additional infrastructure to the PM >> domain code as part of this series. But we may want to mark the Tegra >> PMC driver as .suppress_bind_attrs = true, to make sure it can't be >> removed. > > I see what you are saying. It nearly seemed to me that I should use > BUG_ON() if we fail to remove a genpd in the PMC driver, however, I know > that using BUG_ON should be avoided. I will add the suppress_bind_attrs > = true for the PMC driver as that does make sense for now. Just to let you know, the PMC driver already has suppress_bind_attrs = true. Cheers Jon -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
