Hi, 18a8bd949d6adb311ea816125ff65050df1f3f6e appears to have caused a regression in the serial console for ia64. I have observed the problem on Intel Tiger2 and HP RX2620 when the console or early cons option is specified. For reference Tiger2: console=uart,io,0x2f8,115200n8 RX2620: console=uart,mmio,0xff5e0000,115200n8 uart may also be uart8250, it makes no difference with regards to this problem. console may be earlycons, that also makes no difference as 18a8bd949d6adb311ea816125ff65050df1f3f6e handles both options the almost the same way. On the RX2620 a work around is to omit the console and earlycons parameters all together, as the code in efi_setup_pcdp_console() will autodetect the console and set it up correctly. I believe that the problem is as follows: After 18a8bd949d6adb311ea816125ff65050df1f3f6e, both the console and earlycons options are handled by early_param, using the callback setup_early_serial8250_console(). On ia64, for the hardware that I am observing this problem on (HP RX2620 and Intel Tiger2), I believe that I am seeing the following calls occur. ->arch/ia64/kernel/setup.c:setup_arch() ->parse_early_param() ->setup_early_serial8250_console() N.B callback ->early_serial8250_setup() ->init_port() ->serial_out() ->outb() ->__outb() ->platform_outb() ->ia64_mv.outb() However, ia64_mv may not be set until after machvec_init() is called by setup_arch(), which occurs after the call to parse_early_param(). The reason for this ordering is that machvec_init() may be influenced by the machvec command line argument, which is also handled by early_param. A chicken an egg problem. A fairly simple work-around would be to call machvec_init earlier and have it parse the command like itself. Another solution would be to split up early_serial8250_setup() or setup_early_serial8250_console() somehow, such that init_port() is not called as part of the early_param callback, but rather later explicitly (probably by each architecture's setup_arch()). This is somewhat similar to the way that machvec is handled. I'm sure there are are other good, possibly better solutions. Hence this email. On a related note, I think that the code in efi_setup_pcdp_console() needs to be updated to reflect that console= and earlycons= are basically the same thing now. I have not investigated the effects of 18a8bd949d6adb311ea816125ff65050df1f3f6e on sn_serial_console_early_setup() -- Horms H: http://www.vergenet.net/~horms/ W: http://www.valinux.co.jp/en/ - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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