* [PATCH] acpi: battery: Sanitise model_number by dropping unprintable characters
@ 2026-07-08 7:07 Kate Hsuan
2026-07-09 13:38 ` Rafael J. Wysocki (Intel)
0 siblings, 1 reply; 4+ messages in thread
From: Kate Hsuan @ 2026-07-08 7:07 UTC (permalink / raw)
To: Mark Pearson, Rafael J . Wysocki, Len Brown
Cc: linux-acpi, linux-kernel, Kate Hsuan
The battery Embedded Controller (EC) may return the model name with
trailing unprintable or non-ASCII characters. For example, on some systems:
$ cat /sys/class/power_supply/BAT0/model_name
LNV-5B10W51864��
Strip these unprintable characters to ensure the model_name attribute
contains a valid string. If left intact, these malformed strings prevent
udev rules and hwdb from matching the attribute correctly.
Link: https://gitlab.freedesktop.org/upower/upower/-/work_items/345
Signed-off-by: Kate Hsuan <hpa@redhat.com>
---
drivers/acpi/battery.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index f5e0eb299610..dea0c3cc5160 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -10,6 +10,7 @@
#define pr_fmt(fmt) "ACPI: battery: " fmt
+#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/jiffies.h>
@@ -194,6 +195,21 @@ static int acpi_battery_handle_discharging(struct acpi_battery *battery)
return POWER_SUPPLY_STATUS_DISCHARGING;
}
+static void acpi_battery_remove_special_chars(char *str)
+{
+ char *out = str;
+ unsigned int i = 0;
+
+ while (*str && i < MAX_STRING_LENGTH) {
+ unsigned char c = *str++;
+
+ if (isascii(c) && isprint(c))
+ *out++ = c;
+ i++;
+ }
+ *out = '\0';
+}
+
static int acpi_battery_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
@@ -524,6 +540,9 @@ static int extract_battery_info(const int use_bix,
battery->capacity_now > battery->full_charge_capacity)
battery->capacity_now = battery->full_charge_capacity;
+ if (!result)
+ acpi_battery_remove_special_chars(battery->model_number);
+
return result;
}
--
2.55.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] acpi: battery: Sanitise model_number by dropping unprintable characters
2026-07-08 7:07 [PATCH] acpi: battery: Sanitise model_number by dropping unprintable characters Kate Hsuan
@ 2026-07-09 13:38 ` Rafael J. Wysocki (Intel)
2026-07-10 7:02 ` Kate Hsuan
0 siblings, 1 reply; 4+ messages in thread
From: Rafael J. Wysocki (Intel) @ 2026-07-09 13:38 UTC (permalink / raw)
To: Kate Hsuan
Cc: Mark Pearson, Rafael J . Wysocki, Len Brown, linux-acpi,
linux-kernel
On Wed, Jul 8, 2026 at 9:07 AM Kate Hsuan <hpa@redhat.com> wrote:
>
> The battery Embedded Controller (EC) may return the model name with
> trailing unprintable or non-ASCII characters. For example, on some systems:
>
> $ cat /sys/class/power_supply/BAT0/model_name
> LNV-5B10W51864��
If they are just trailing and not in the middle of the string, you
could just find the first one and overwrite it with a NUL character.
Rewriting the entire string is overkill in that case.
> Strip these unprintable characters to ensure the model_name attribute
> contains a valid string. If left intact, these malformed strings prevent
> udev rules and hwdb from matching the attribute correctly.
>
> Link: https://gitlab.freedesktop.org/upower/upower/-/work_items/345
>
> Signed-off-by: Kate Hsuan <hpa@redhat.com>
> ---
> drivers/acpi/battery.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
> index f5e0eb299610..dea0c3cc5160 100644
> --- a/drivers/acpi/battery.c
> +++ b/drivers/acpi/battery.c
> @@ -10,6 +10,7 @@
>
> #define pr_fmt(fmt) "ACPI: battery: " fmt
>
> +#include <linux/ctype.h>
> #include <linux/delay.h>
> #include <linux/dmi.h>
> #include <linux/jiffies.h>
> @@ -194,6 +195,21 @@ static int acpi_battery_handle_discharging(struct acpi_battery *battery)
> return POWER_SUPPLY_STATUS_DISCHARGING;
> }
>
> +static void acpi_battery_remove_special_chars(char *str)
> +{
> + char *out = str;
> + unsigned int i = 0;
> +
And I would use a for () loop below anyway.
> + while (*str && i < MAX_STRING_LENGTH) {
> + unsigned char c = *str++;
> +
> + if (isascii(c) && isprint(c))
> + *out++ = c;
> + i++;
> + }
> + *out = '\0';
> +}
> +
> static int acpi_battery_get_property(struct power_supply *psy,
> enum power_supply_property psp,
> union power_supply_propval *val)
> @@ -524,6 +540,9 @@ static int extract_battery_info(const int use_bix,
> battery->capacity_now > battery->full_charge_capacity)
> battery->capacity_now = battery->full_charge_capacity;
>
> + if (!result)
> + acpi_battery_remove_special_chars(battery->model_number);
> +
> return result;
> }
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] acpi: battery: Sanitise model_number by dropping unprintable characters
2026-07-09 13:38 ` Rafael J. Wysocki (Intel)
@ 2026-07-10 7:02 ` Kate Hsuan
0 siblings, 0 replies; 4+ messages in thread
From: Kate Hsuan @ 2026-07-10 7:02 UTC (permalink / raw)
To: Rafael J. Wysocki (Intel)
Cc: Mark Pearson, Len Brown, linux-acpi, linux-kernel
Hi Rafael,
Thank you for the review.
On Thu, Jul 9, 2026 at 9:38 PM Rafael J. Wysocki (Intel)
<rafael@kernel.org> wrote:
>
> On Wed, Jul 8, 2026 at 9:07 AM Kate Hsuan <hpa@redhat.com> wrote:
> >
> > The battery Embedded Controller (EC) may return the model name with
> > trailing unprintable or non-ASCII characters. For example, on some systems:
> >
> > $ cat /sys/class/power_supply/BAT0/model_name
> > LNV-5B10W51864��
>
> If they are just trailing and not in the middle of the string, you
> could just find the first one and overwrite it with a NUL character.
>
> Rewriting the entire string is overkill in that case.
You are right. I'll find the first unprintable character and replace
it with a NUL and break the loop.
>
> > Strip these unprintable characters to ensure the model_name attribute
> > contains a valid string. If left intact, these malformed strings prevent
> > udev rules and hwdb from matching the attribute correctly.
> >
> > Link: https://gitlab.freedesktop.org/upower/upower/-/work_items/345
> >
> > Signed-off-by: Kate Hsuan <hpa@redhat.com>
> > ---
> > drivers/acpi/battery.c | 19 +++++++++++++++++++
> > 1 file changed, 19 insertions(+)
> >
> > diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
> > index f5e0eb299610..dea0c3cc5160 100644
> > --- a/drivers/acpi/battery.c
> > +++ b/drivers/acpi/battery.c
> > @@ -10,6 +10,7 @@
> >
> > #define pr_fmt(fmt) "ACPI: battery: " fmt
> >
> > +#include <linux/ctype.h>
> > #include <linux/delay.h>
> > #include <linux/dmi.h>
> > #include <linux/jiffies.h>
> > @@ -194,6 +195,21 @@ static int acpi_battery_handle_discharging(struct acpi_battery *battery)
> > return POWER_SUPPLY_STATUS_DISCHARGING;
> > }
> >
> > +static void acpi_battery_remove_special_chars(char *str)
> > +{
> > + char *out = str;
> > + unsigned int i = 0;
> > +
>
> And I would use a for () loop below anyway.
Okay
>
> > + while (*str && i < MAX_STRING_LENGTH) {
> > + unsigned char c = *str++;
> > +
> > + if (isascii(c) && isprint(c))
> > + *out++ = c;
> > + i++;
> > + }
> > + *out = '\0';
> > +}
> > +
> > static int acpi_battery_get_property(struct power_supply *psy,
> > enum power_supply_property psp,
> > union power_supply_propval *val)
> > @@ -524,6 +540,9 @@ static int extract_battery_info(const int use_bix,
> > battery->capacity_now > battery->full_charge_capacity)
> > battery->capacity_now = battery->full_charge_capacity;
> >
> > + if (!result)
> > + acpi_battery_remove_special_chars(battery->model_number);
> > +
> > return result;
> > }
> >
>
--
BR,
Kate
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] acpi: battery: Sanitise model_number by dropping unprintable characters
@ 2026-07-08 7:07 Kate Hsuan
0 siblings, 0 replies; 4+ messages in thread
From: Kate Hsuan @ 2026-07-08 7:07 UTC (permalink / raw)
To: hpa; +Cc: linux-acpi, linux-kernel
The battery Embedded Controller (EC) may return the model name with
trailing unprintable or non-ASCII characters. For example, on some systems:
$ cat /sys/class/power_supply/BAT0/model_name
LNV-5B10W51864��
Strip these unprintable characters to ensure the model_name attribute
contains a valid string. If left intact, these malformed strings prevent
udev rules and hwdb from matching the attribute correctly.
Link: https://gitlab.freedesktop.org/upower/upower/-/work_items/345
Signed-off-by: Kate Hsuan <hpa@redhat.com>
---
drivers/acpi/battery.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index f5e0eb299610..dea0c3cc5160 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -10,6 +10,7 @@
#define pr_fmt(fmt) "ACPI: battery: " fmt
+#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/jiffies.h>
@@ -194,6 +195,21 @@ static int acpi_battery_handle_discharging(struct acpi_battery *battery)
return POWER_SUPPLY_STATUS_DISCHARGING;
}
+static void acpi_battery_remove_special_chars(char *str)
+{
+ char *out = str;
+ unsigned int i = 0;
+
+ while (*str && i < MAX_STRING_LENGTH) {
+ unsigned char c = *str++;
+
+ if (isascii(c) && isprint(c))
+ *out++ = c;
+ i++;
+ }
+ *out = '\0';
+}
+
static int acpi_battery_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
@@ -524,6 +540,9 @@ static int extract_battery_info(const int use_bix,
battery->capacity_now > battery->full_charge_capacity)
battery->capacity_now = battery->full_charge_capacity;
+ if (!result)
+ acpi_battery_remove_special_chars(battery->model_number);
+
return result;
}
--
2.55.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2026-07-09 13:38 ` Rafael J. Wysocki (Intel)
2026-07-10 7:02 ` Kate Hsuan
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