linux-kernel - [PATCH] ACPI: SBS: Fix present test in acpi_battery

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Message-ID: <aQSzr4NynN2mpEvG@stanley.mountain>
Date: Fri, 31 Oct 2025 16:03:43 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Alexey Starikovskiy <astarikovskiy@...e.de>,
	Harshit Mogalapalli <harshit.m.mogalapalli@...il.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [PATCH] ACPI: SBS: Fix present test in acpi_battery_read()

The battery->present variable is a 1 bit bitfield in a u8.  This means
that the "state & (1 << battery->id)" test will only work when
"battery->id" is zero, otherwise ->present is zero.  Fix this by adding
a !!.

Fixes: db1c291af7ad ("ACPI: SBS: Make SBS reads table-driven.")
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
---
This is a new static checker warning that Harshit and I wrote.  It's
untested.

 drivers/acpi/sbs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/sbs.c b/drivers/acpi/sbs.c
index a3f95a3fffde..d3edc3bcbf01 100644
--- a/drivers/acpi/sbs.c
+++ b/drivers/acpi/sbs.c
@@ -487,7 +487,7 @@ static int acpi_battery_read(struct acpi_battery *battery)
 		if (result)
 			return result;
 
-		battery->present = state & (1 << battery->id);
+		battery->present = !!(state & (1 << battery->id));
 		if (!battery->present)
 			return 0;
 
-- 
2.51.0