* [PATCH] drm: panel: himax-hx8279: avoid using an uninitialized variable
@ 2025-04-23 16:32 Arnd Bergmann
2025-04-23 17:19 ` Dmitry Baryshkov
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Arnd Bergmann @ 2025-04-23 16:32 UTC (permalink / raw)
To: Neil Armstrong, Maarten Lankhorst, Maxime Ripard,
Thomas Zimmermann, David Airlie, Simona Vetter,
AngeloGioacchino Del Regno
Cc: Arnd Bergmann, Jessica Zhang, dri-devel, linux-kernel
From: Arnd Bergmann <arnd@arndb.de>
goa_even_valid is only initialized in one branch but not the other:
drivers/gpu/drm/panel/panel-himax-hx8279.c:838:6: error: variable 'goa_even_valid' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
838 | if (num_zero == ARRAY_SIZE(desc->goa_even_timing))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/panel/panel-himax-hx8279.c:842:23: note: uninitialized use occurs here
842 | if (goa_odd_valid != goa_even_valid)
| ^~~~~~~~~~~~~~
Change the initialization to set it to the value of the condition instead.
Fixes: 38d42c261389 ("drm: panel: Add driver for Himax HX8279 DDIC panels")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/gpu/drm/panel/panel-himax-hx8279.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/panel/panel-himax-hx8279.c b/drivers/gpu/drm/panel/panel-himax-hx8279.c
index b48b350b62da..4f548430654a 100644
--- a/drivers/gpu/drm/panel/panel-himax-hx8279.c
+++ b/drivers/gpu/drm/panel/panel-himax-hx8279.c
@@ -835,8 +835,7 @@ static int hx8279_check_goa_config(struct hx8279 *hx, struct device *dev)
num_zero++;
}
- if (num_zero == ARRAY_SIZE(desc->goa_even_timing))
- goa_even_valid = false;
+ goa_even_valid = (num_zero != ARRAY_SIZE(desc->goa_even_timing));
/* Programming one without the other would make no sense! */
if (goa_odd_valid != goa_even_valid)
--
2.39.5
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] drm: panel: himax-hx8279: avoid using an uninitialized variable
2025-04-23 16:32 [PATCH] drm: panel: himax-hx8279: avoid using an uninitialized variable Arnd Bergmann
@ 2025-04-23 17:19 ` Dmitry Baryshkov
2025-04-24 7:21 ` AngeloGioacchino Del Regno
2025-04-24 8:20 ` Neil Armstrong
2 siblings, 0 replies; 4+ messages in thread
From: Dmitry Baryshkov @ 2025-04-23 17:19 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Neil Armstrong, Maarten Lankhorst, Maxime Ripard,
Thomas Zimmermann, David Airlie, Simona Vetter,
AngeloGioacchino Del Regno, Arnd Bergmann, Jessica Zhang,
dri-devel, linux-kernel
On Wed, Apr 23, 2025 at 06:32:07PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> goa_even_valid is only initialized in one branch but not the other:
>
> drivers/gpu/drm/panel/panel-himax-hx8279.c:838:6: error: variable 'goa_even_valid' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
> 838 | if (num_zero == ARRAY_SIZE(desc->goa_even_timing))
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/panel/panel-himax-hx8279.c:842:23: note: uninitialized use occurs here
> 842 | if (goa_odd_valid != goa_even_valid)
> | ^~~~~~~~~~~~~~
>
> Change the initialization to set it to the value of the condition instead.
>
> Fixes: 38d42c261389 ("drm: panel: Add driver for Himax HX8279 DDIC panels")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/gpu/drm/panel/panel-himax-hx8279.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
>
--
With best wishes
Dmitry
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] drm: panel: himax-hx8279: avoid using an uninitialized variable
2025-04-23 16:32 [PATCH] drm: panel: himax-hx8279: avoid using an uninitialized variable Arnd Bergmann
2025-04-23 17:19 ` Dmitry Baryshkov
@ 2025-04-24 7:21 ` AngeloGioacchino Del Regno
2025-04-24 8:20 ` Neil Armstrong
2 siblings, 0 replies; 4+ messages in thread
From: AngeloGioacchino Del Regno @ 2025-04-24 7:21 UTC (permalink / raw)
To: Arnd Bergmann, Neil Armstrong, Maarten Lankhorst, Maxime Ripard,
Thomas Zimmermann, David Airlie, Simona Vetter
Cc: Arnd Bergmann, Jessica Zhang, dri-devel, linux-kernel
Il 23/04/25 18:32, Arnd Bergmann ha scritto:
> From: Arnd Bergmann <arnd@arndb.de>
>
> goa_even_valid is only initialized in one branch but not the other:
>
> drivers/gpu/drm/panel/panel-himax-hx8279.c:838:6: error: variable 'goa_even_valid' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
> 838 | if (num_zero == ARRAY_SIZE(desc->goa_even_timing))
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/panel/panel-himax-hx8279.c:842:23: note: uninitialized use occurs here
> 842 | if (goa_odd_valid != goa_even_valid)
> | ^~~~~~~~~~~~~~
>
> Change the initialization to set it to the value of the condition instead.
>
> Fixes: 38d42c261389 ("drm: panel: Add driver for Himax HX8279 DDIC panels")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
> drivers/gpu/drm/panel/panel-himax-hx8279.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-himax-hx8279.c b/drivers/gpu/drm/panel/panel-himax-hx8279.c
> index b48b350b62da..4f548430654a 100644
> --- a/drivers/gpu/drm/panel/panel-himax-hx8279.c
> +++ b/drivers/gpu/drm/panel/panel-himax-hx8279.c
> @@ -835,8 +835,7 @@ static int hx8279_check_goa_config(struct hx8279 *hx, struct device *dev)
> num_zero++;
> }
>
> - if (num_zero == ARRAY_SIZE(desc->goa_even_timing))
> - goa_even_valid = false;
> + goa_even_valid = (num_zero != ARRAY_SIZE(desc->goa_even_timing));
>
> /* Programming one without the other would make no sense! */
> if (goa_odd_valid != goa_even_valid)
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] drm: panel: himax-hx8279: avoid using an uninitialized variable
2025-04-23 16:32 [PATCH] drm: panel: himax-hx8279: avoid using an uninitialized variable Arnd Bergmann
2025-04-23 17:19 ` Dmitry Baryshkov
2025-04-24 7:21 ` AngeloGioacchino Del Regno
@ 2025-04-24 8:20 ` Neil Armstrong
2 siblings, 0 replies; 4+ messages in thread
From: Neil Armstrong @ 2025-04-24 8:20 UTC (permalink / raw)
To: Arnd Bergmann, Maarten Lankhorst, Maxime Ripard,
Thomas Zimmermann, David Airlie, Simona Vetter,
AngeloGioacchino Del Regno
Cc: Arnd Bergmann, Jessica Zhang, dri-devel, linux-kernel
Hi,
On 23/04/2025 18:32, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> goa_even_valid is only initialized in one branch but not the other:
>
> drivers/gpu/drm/panel/panel-himax-hx8279.c:838:6: error: variable 'goa_even_valid' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
> 838 | if (num_zero == ARRAY_SIZE(desc->goa_even_timing))
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/panel/panel-himax-hx8279.c:842:23: note: uninitialized use occurs here
> 842 | if (goa_odd_valid != goa_even_valid)
> | ^~~~~~~~~~~~~~
>
> Change the initialization to set it to the value of the condition instead.
>
> Fixes: 38d42c261389 ("drm: panel: Add driver for Himax HX8279 DDIC panels")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/gpu/drm/panel/panel-himax-hx8279.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-himax-hx8279.c b/drivers/gpu/drm/panel/panel-himax-hx8279.c
> index b48b350b62da..4f548430654a 100644
> --- a/drivers/gpu/drm/panel/panel-himax-hx8279.c
> +++ b/drivers/gpu/drm/panel/panel-himax-hx8279.c
> @@ -835,8 +835,7 @@ static int hx8279_check_goa_config(struct hx8279 *hx, struct device *dev)
> num_zero++;
> }
>
> - if (num_zero == ARRAY_SIZE(desc->goa_even_timing))
> - goa_even_valid = false;
> + goa_even_valid = (num_zero != ARRAY_SIZE(desc->goa_even_timing));
>
> /* Programming one without the other would make no sense! */
> if (goa_odd_valid != goa_even_valid)
Thanks, Applying https://lore.kernel.org/all/20250423-panel-himax-hx8279-fix-sometimes-uninitialized-v2-1-fc501c6558d9@kernel.org/
instead since more complete.
Neil
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-04-23 16:32 [PATCH] drm: panel: himax-hx8279: avoid using an uninitialized variable Arnd Bergmann
2025-04-23 17:19 ` Dmitry Baryshkov
2025-04-24 7:21 ` AngeloGioacchino Del Regno
2025-04-24 8:20 ` Neil Armstrong
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