Andy Shevchenko <andy.shevchenko@xxxxxxxxx> writes: > On Sat, Apr 27, 2019 at 12:01 PM Esben Haabendal <esben@xxxxxxxxxxxx> wrote: >> Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> writes: >> > On Fri, Apr 26, 2019 at 06:54:05PM +0200, Esben Haabendal wrote: >> >> Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> writes: >> >> The reason for this patch is to be able to do exactly that (set port >> >> type and UPF_FIXED_TYPE) without having UPF_BOOT_AUTOCONF added. >> >> >> >> In the current serial8250_register_8250_port() there is: >> >> >> >> uart->port.flags = up->port.flags | UPF_BOOT_AUTOCONF; >> >> >> >> So, even though I set UPF_FIXED_TYPE, I get >> >> UPF_FIXED_TYPE|UPF_BOOT_AUTOCONF. >> > >> > Yes. >> > >> >> So I need this patch. >> > >> > Why? I don't see any problems to have these flags set. >> >> The problem with having UPF_BOOT_AUTOCONF is the call to >> serial8250_request_std_resource(). It calls request_mem_region(), which >> fails if the MFD driver already have requested the memory region for the >> MFD device. > > If it's MFD, why it requested the region for its child? > Isn't it a bug in MFD driver? It is a PCI driver, which calls pci_request_regions(). The PCI device carries a lot of different functions, which uses small slices of the PCI memory region(s). With the resources being a tree structure, I don't think it is a bug when a parent driver requests the entire memory region. It would be nice if child drivers requesting memory would pass the parent memory resource. Maybe 8250 driver could be changed to accept a struct resource pointer instead of a simple mapbase value, allowing to setup the resource with parent pointing to the MFD memory resource. /Esben
