2020-01-17 13:35:34

by Colin King

Subject: [PATCH][next] drm/amd/display: fix for-loop with incorrectly sized loop counter

From: Colin Ian King <[email protected]>

A for-loop is iterating from 0 up to 1000 however the loop variable count
is a u8 and hence not large enough. Fix this by making count an int.
Also remove the redundant initialization of count since this is never used
and add { } on the loop statement make the loop block clearer.

Addresses-Coverity: ("Operands don't affect result")
Fixes: ed581a0ace44 ("drm/amd/display: wait for update when setting dpg test pattern")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 6ab298c65247..cbed738a4246 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -3680,7 +3680,7 @@ static void set_crtc_test_pattern(struct dc_link *link,
struct pipe_ctx *odm_pipe;
enum controller_dp_color_space controller_color_space;
int opp_cnt = 1;
- uint8_t count = 0;
+ int count;

switch (test_pattern_color_space) {
case DP_TEST_PATTERN_COLOR_SPACE_RGB:
@@ -3725,11 +3725,12 @@ static void set_crtc_test_pattern(struct dc_link *link,
width,
height);
/* wait for dpg to blank pixel data with test pattern */
- for (count = 0; count < 1000; count++)
+ for (count = 0; count < 1000; count++) {
if (opp->funcs->dpg_is_blanked(opp))
break;
else
udelay(100);
+ }
}
}
break;
--
2.24.0

2020-01-17 14:36:49

by walter harms

Subject: Re: [PATCH][next] drm/amd/display: fix for-loop with incorrectly sized loop counter

Am 17.01.2020 14:33, schrieb Colin King:
> From: Colin Ian King <[email protected]>
>
> A for-loop is iterating from 0 up to 1000 however the loop variable count
> is a u8 and hence not large enough. Fix this by making count an int.
> Also remove the redundant initialization of count since this is never used
> and add { } on the loop statement make the loop block clearer.
>
> Addresses-Coverity: ("Operands don't affect result")
> Fixes: ed581a0ace44 ("drm/amd/display: wait for update when setting dpg test pattern")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> index 6ab298c65247..cbed738a4246 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> @@ -3680,7 +3680,7 @@ static void set_crtc_test_pattern(struct dc_link *link,
> struct pipe_ctx *odm_pipe;
> enum controller_dp_color_space controller_color_space;
> int opp_cnt = 1;
> - uint8_t count = 0;
> + int count;
>
> switch (test_pattern_color_space) {
> case DP_TEST_PATTERN_COLOR_SPACE_RGB:
> @@ -3725,11 +3725,12 @@ static void set_crtc_test_pattern(struct dc_link *link,
> width,
> height);
> /* wait for dpg to blank pixel data with test pattern */
> - for (count = 0; count < 1000; count++)
> + for (count = 0; count < 1000; count++) {
> if (opp->funcs->dpg_is_blanked(opp))
> break;
> else
> udelay(100);
> + }
> }
> }
> break;

Nitpick:
the else is useless you can remove it.

re,
wh

2020-01-27 20:15:00

by Alex Deucher

Subject: Re: [PATCH][next] drm/amd/display: fix for-loop with incorrectly sized loop counter

Applied with Walter's comment included.

Thanks!

Alex

On Fri, Jan 17, 2020 at 9:45 AM walter harms <[email protected]> wrote:
>
>
>
> Am 17.01.2020 14:33, schrieb Colin King:
> > From: Colin Ian King <[email protected]>
> >
> > A for-loop is iterating from 0 up to 1000 however the loop variable count
> > is a u8 and hence not large enough. Fix this by making count an int.
> > Also remove the redundant initialization of count since this is never used
> > and add { } on the loop statement make the loop block clearer.
> >
> > Addresses-Coverity: ("Operands don't affect result")
> > Fixes: ed581a0ace44 ("drm/amd/display: wait for update when setting dpg test pattern")
> > Signed-off-by: Colin Ian King <[email protected]>
> > ---
> > drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> > index 6ab298c65247..cbed738a4246 100644
> > --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> > +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> > @@ -3680,7 +3680,7 @@ static void set_crtc_test_pattern(struct dc_link *link,
> > struct pipe_ctx *odm_pipe;
> > enum controller_dp_color_space controller_color_space;
> > int opp_cnt = 1;
> > - uint8_t count = 0;
> > + int count;
> >
> > switch (test_pattern_color_space) {
> > case DP_TEST_PATTERN_COLOR_SPACE_RGB:
> > @@ -3725,11 +3725,12 @@ static void set_crtc_test_pattern(struct dc_link *link,
> > width,
> > height);
> > /* wait for dpg to blank pixel data with test pattern */
> > - for (count = 0; count < 1000; count++)
> > + for (count = 0; count < 1000; count++) {
> > if (opp->funcs->dpg_is_blanked(opp))
> > break;
> > else
> > udelay(100);
> > + }
> > }
> > }
> > break;
>
> Nitpick:
> the else is useless you can remove it.
>
> re,
> wh
>
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