From: "Jiaxun Yang" <jiaxun.yang@flygoat.com>
To: "Waldemar Brodkorb" <wbx@openadk.org>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>
Subject: Re: serial console on Mikrotik RB532 non-working
Date: Tue, 03 Feb 2026 15:24:19 +0000 [thread overview]
Message-ID: <f0413775-1a6f-49a6-841b-bf52214a2841@app.fastmail.com> (raw)
In-Reply-To: <aX-d0ShTplHKZT33@waldemar-brodkorb.de>
On Sun, 1 Feb 2026, at 6:39 PM, Waldemar Brodkorb wrote:
> Hi MIPS hackers,
>
> I want to use the latest Linux kernel on my Mikrotik RB532, but the
> serial console is non working. I bisected the problem and the first
> breaking change is this commit:
Hi,
Can you try this?
diff --git a/arch/mips/rb532/devices.c b/arch/mips/rb532/devices.c
index 8ecb56be81ac..030e0b41ff06 100644
--- a/arch/mips/rb532/devices.c
+++ b/arch/mips/rb532/devices.c
@@ -213,7 +213,8 @@ static struct platform_device rb532_wdt = {
static struct plat_serial8250_port rb532_uart_res[] = {
{
.type = PORT_16550A,
- .membase = (char *)KSEG1ADDR(REGBASE + UART0BASE),
+ .mapbase = REGBASE + UART0BASE,
+ .mapsize = SZ_4K,
.irq = UART0_IRQ,
.regshift = 2,
.iotype = UPIO_MEM,
Thanks
Jiaxun
>
> 6e690d54cfa802f939cefbd2fa2c91bd0b8bd1b6 is the first bad commit
> commit 6e690d54cfa802f939cefbd2fa2c91bd0b8bd1b6
> Author: Yi Yang <yiyang13@huawei.com>
> Date: Tue Jun 28 16:35:15 2022 +0800
>
> serial: 8250: fix return error code in serial8250_request_std_resource()
>
> If port->mapbase = NULL in serial8250_request_std_resource() , it need
> return a error code instead of 0. If uart_set_info() fail to request new
> regions by serial8250_request_std_resource() but the return value of
> serial8250_request_std_resource() is 0, The system incorrectly considers
> that the resource application is successful and does not attempt to
> restore the old setting. A null pointer reference is triggered when the
> port resource is later invoked.
>
> Signed-off-by: Yi Yang <yiyang13@huawei.com>
> Cc: stable <stable@kernel.org>
> Link: https://lore.kernel.org/r/20220628083515.64138-1-yiyang13@huawei.com
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> drivers/tty/serial/8250/8250_port.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> When I compile the commit before this commit everything is fine.
> When I just try to revert it on master I still get no output on my
> serial console.
>
> Anyone here have an idea what is defect in arch/mips/rb532 nowadays?
>
> Thanks in advance,
> Waldemar
--
- Jiaxun
next prev parent reply other threads:[~2026-02-03 15:31 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-01 18:39 serial console on Mikrotik RB532 non-working Waldemar Brodkorb
2026-02-03 15:24 ` Jiaxun Yang [this message]
2026-02-03 15:28 ` Jiaxun Yang
2026-02-03 18:25 ` Waldemar Brodkorb
2026-02-04 10:14 ` Jonas Gorski
2026-02-04 11:19 ` Waldemar Brodkorb
2026-02-04 11:33 ` Jonas Gorski
2026-02-04 16:38 ` Waldemar Brodkorb
2026-02-05 6:27 ` Rong Zhang
2026-02-05 7:29 ` Waldemar Brodkorb
2026-02-21 9:23 ` Waldemar Brodkorb
2026-02-21 10:28 ` Maciej W. Rozycki
2026-02-21 16:08 ` Waldemar Brodkorb
2026-02-12 7:35 ` Waldemar Brodkorb
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