git: 8c3d6917c1f1 - main - stand: eficom: Only set baudrate when it changes
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Date: Thu, 11 May 2023 20:06:52 UTC
The branch main has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=8c3d6917c1f127f70719193959ff42f3f1ab8f5f commit 8c3d6917c1f127f70719193959ff42f3f1ab8f5f Author: Warner Losh <imp@FreeBSD.org> AuthorDate: 2023-05-11 20:04:00 +0000 Commit: Warner Losh <imp@FreeBSD.org> CommitDate: 2023-05-11 20:06:03 +0000 stand: eficom: Only set baudrate when it changes Only set the baudrate when it is different than what the device has reported. In addition, pass in the args to effect no change to the other parameters to the serial port. Some EFI firmware gets cranky when you set them to the same value, so avoid doing so (we likely can remove the HyperV workaround with this fix, but I kept it in place). Add comments to the code for why we do this too. Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D40010 --- stand/efi/libefi/eficom.c | 39 ++++++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 17 deletions(-) diff --git a/stand/efi/libefi/eficom.c b/stand/efi/libefi/eficom.c index b0fc0d8fbf6a..b1c84399a05d 100644 --- a/stand/efi/libefi/eficom.c +++ b/stand/efi/libefi/eficom.c @@ -41,6 +41,7 @@ static EFI_GUID serial = SERIAL_IO_PROTOCOL; #define PNP0501 0x501 /* 16550A-compatible COM port */ struct serial { + uint64_t newbaudrate; uint64_t baudrate; uint32_t timeout; uint32_t receivefifodepth; @@ -300,7 +301,8 @@ comc_probe(struct console *sc) if (EFI_ERROR(status)) { comc_port->sio = NULL; } else { - comc_port->baudrate = comc_port->sio->Mode->BaudRate; + comc_port->newbaudrate = + comc_port->baudrate = comc_port->sio->Mode->BaudRate; comc_port->timeout = comc_port->sio->Mode->Timeout; comc_port->receivefifodepth = comc_port->sio->Mode->ReceiveFifoDepth; @@ -322,7 +324,7 @@ comc_probe(struct console *sc) env = getenv("comconsole_speed"); if (comc_parse_intval(env, &val) == CMD_OK) - comc_port->baudrate = val; + comc_port->newbaudrate = val; if (env != NULL) unsetenv("efi_com_speed"); @@ -497,10 +499,9 @@ comc_speed_set(struct env_var *ev, int flags, const void *value) if (comc_parse_intval(value, &speed) != CMD_OK) return (CMD_ERROR); - comc_port->baudrate = speed; - (void) comc_setup(); - - env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL); + comc_port->newbaudrate = speed; + if (comc_setup()) + env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL); return (CMD_OK); } @@ -525,20 +526,24 @@ comc_setup(void) return (false); } - if (comc_port->sio->SetAttributes != NULL) { + /* + * Avoid setting the baud rate on Hyper-V. Also, only set the baud rate + * if the baud rate has changed from the default. And pass in '0' or + * DefaultFoo when we're not changing those values. Some EFI + * implementations get cranky when you set things to the values reported + * back even when they are unchanged. + */ + if (comc_port->sio->SetAttributes != NULL && + comc_port->newbaudrate != comc_port->baudrate) { ev = getenv("smbios.bios.version"); - if (ev != NULL && strncmp(ev, "Hyper-V", 7) == 0) { + if (ev != NULL && strncmp(ev, "Hyper-V", 7) != 0) { status = comc_port->sio->SetAttributes(comc_port->sio, - 0, 0, 0, DefaultParity, 0, DefaultStopBits); - } else { - status = comc_port->sio->SetAttributes(comc_port->sio, - comc_port->baudrate, comc_port->receivefifodepth, - comc_port->timeout, comc_port->parity, - comc_port->databits, comc_port->stopbits); + comc_port->newbaudrate, 0, 0, DefaultParity, 0, + DefaultStopBits); + if (EFI_ERROR(status)) + return (false); + comc_port->baudrate = comc_port->newbaudrate; } - - if (EFI_ERROR(status)) - return (false); } #ifdef EFI_FORCE_RTS