[PATCH] arm64: acpi: Fix incorrect check for default console message

[PATCH] arm64: acpi: Fix incorrect check for default console message

[Punit Agrawal]

bad3fa2fb920 ("ACPI: Suppress misleading SPCR console message when
SPCR table is absent") mistakenly assumes acpi_parse_spcr() returning
0 to indicate a failure to parse SPCR and prints a message to the
kernel logs accordingly. In reality acpi_parse_spcr() returns 0 on
success and -ERRNO on failure.

Fix the faulty check to output the correct logging message.

Fixes: bad3fa2fb920 ("ACPI: Suppress misleading SPCR console message when SPCR table is absent")
Signed-off-by: Punit Agrawal <punit.agrawal@oss.qualcomm.com>
---
Hi,

After sending a patch to fix incorrect parsing of SPCR[0], I was still
seeing inconsistent logging on arm64. The result is this nugget.

Considering the pointless churn - I wondered if it isn't better to
drop the message? If others agree, I can send a patch (and revert
bad3fa2fb920 while at it).

Thanks,
Punit

[0] https://lore.kernel.org/all/20251024123125.1081612-1-punit.agrawal@oss.qualcomm.com/

 arch/arm64/kernel/acpi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 7aca29e1d30b..2fba72d51d71 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -254,7 +254,7 @@ void __init acpi_boot_table_init(void)
 		 */
 		ret = acpi_parse_spcr(earlycon_acpi_spcr_enable,
 			!param_acpi_nospcr);
-		if (!ret || param_acpi_nospcr || !IS_ENABLED(CONFIG_ACPI_SPCR_TABLE))
+		if (ret < 0 || param_acpi_nospcr || !IS_ENABLED(CONFIG_ACPI_SPCR_TABLE))
 			pr_info("Use ACPI SPCR as default console: No\n");
 		else
 			pr_info("Use ACPI SPCR as default console: Yes\n");
-- 
2.34.1

Re: [PATCH] arm64: acpi: Fix incorrect check for default console message

[Will Deacon]

On Mon, Oct 27, 2025 at 02:19:41PM +0000, Punit Agrawal wrote:
> bad3fa2fb920 ("ACPI: Suppress misleading SPCR console message when
> SPCR table is absent") mistakenly assumes acpi_parse_spcr() returning
> 0 to indicate a failure to parse SPCR and prints a message to the
> kernel logs accordingly. In reality acpi_parse_spcr() returns 0 on
> success and -ERRNO on failure.
> 
> Fix the faulty check to output the correct logging message.
> 
> Fixes: bad3fa2fb920 ("ACPI: Suppress misleading SPCR console message when SPCR table is absent")
> Signed-off-by: Punit Agrawal <punit.agrawal@oss.qualcomm.com>
> ---
> Hi,
> 
> After sending a patch to fix incorrect parsing of SPCR[0], I was still
> seeing inconsistent logging on arm64. The result is this nugget.
> 
> Considering the pointless churn - I wondered if it isn't better to
> drop the message? If others agree, I can send a patch (and revert
> bad3fa2fb920 while at it).

I'd be happy dropping the message as it looks pretty useless to me,
especially given that the current logic is broken.

Will

Re: [PATCH] arm64: acpi: Fix incorrect check for default console message

[Hanjun Guo]

On 2025/10/30 22:21, Will Deacon wrote:
> On Mon, Oct 27, 2025 at 02:19:41PM +0000, Punit Agrawal wrote:
>> bad3fa2fb920 ("ACPI: Suppress misleading SPCR console message when
>> SPCR table is absent") mistakenly assumes acpi_parse_spcr() returning
>> 0 to indicate a failure to parse SPCR and prints a message to the
>> kernel logs accordingly. In reality acpi_parse_spcr() returns 0 on
>> success and -ERRNO on failure.
>>
>> Fix the faulty check to output the correct logging message.
>>
>> Fixes: bad3fa2fb920 ("ACPI: Suppress misleading SPCR console message when SPCR table is absent")
>> Signed-off-by: Punit Agrawal <punit.agrawal@oss.qualcomm.com>
>> ---
>> Hi,
>>
>> After sending a patch to fix incorrect parsing of SPCR[0], I was still
>> seeing inconsistent logging on arm64. The result is this nugget.
>>
>> Considering the pointless churn - I wondered if it isn't better to
>> drop the message? If others agree, I can send a patch (and revert
>> bad3fa2fb920 while at it).
> 
> I'd be happy dropping the message as it looks pretty useless to me,
> especially given that the current logic is broken.

Fine with me as well, in the acpi_parse_spcr() there is a default
pr_info() for the console information, we can drop it here.

Thanks
Hanjun

Re: [PATCH] arm64: acpi: Fix incorrect check for default console message

[Punit Agrawal]

Hi Hanjun,

Hanjun Guo <guohanjun@huawei.com> writes:

> On 2025/10/30 22:21, Will Deacon wrote:
>> On Mon, Oct 27, 2025 at 02:19:41PM +0000, Punit Agrawal wrote:
>>> bad3fa2fb920 ("ACPI: Suppress misleading SPCR console message when
>>> SPCR table is absent") mistakenly assumes acpi_parse_spcr() returning
>>> 0 to indicate a failure to parse SPCR and prints a message to the
>>> kernel logs accordingly. In reality acpi_parse_spcr() returns 0 on
>>> success and -ERRNO on failure.
>>>
>>> Fix the faulty check to output the correct logging message.
>>>
>>> Fixes: bad3fa2fb920 ("ACPI: Suppress misleading SPCR console message when SPCR table is absent")
>>> Signed-off-by: Punit Agrawal <punit.agrawal@oss.qualcomm.com>
>>> ---
>>> Hi,
>>>
>>> After sending a patch to fix incorrect parsing of SPCR[0], I was still
>>> seeing inconsistent logging on arm64. The result is this nugget.
>>>
>>> Considering the pointless churn - I wondered if it isn't better to
>>> drop the message? If others agree, I can send a patch (and revert
>>> bad3fa2fb920 while at it).
>> I'd be happy dropping the message as it looks pretty useless to me,
>> especially given that the current logic is broken.
>
> Fine with me as well, in the acpi_parse_spcr() there is a default
> pr_info() for the console information, we can drop it here.

Thanks! I sent a follow up[0] that's been picked up as a fix for v6.18
(already merged).

[0] https://lore.kernel.org/all/20251031111138.1262202-1-punit.agrawal@oss.qualcomm.com/