* [PATCH] drm/bridge: ti-sn65dsi86: fix a ternary type promotion bug
@ 2021-05-18 9:19 ` Dan Carpenter
0 siblings, 0 replies; 6+ messages in thread
From: Dan Carpenter @ 2021-05-18 9:19 UTC (permalink / raw)
To: Andrzej Hajda
Cc: Neil Armstrong, Robert Foss, Laurent Pinchart, Jonas Karlman,
Jernej Skrabec, David Airlie, Daniel Vetter, Bjorn Andersson,
Linus Walleij, Douglas Anderson, dri-devel, linux-kernel,
kernel-janitors
The ti_sn_aux_transfer() function returns ssize_t (signed long). It's
supposed to return negative error codes or the number of bytes
transferred. The "ret" variable is int and the "len" variable is
unsigned int.
The problem is that with a ternary like this, the negative int is first
type promoted to unsigned int to match "len" at this point it is a high
positive value. Then when it is type promoted to ssize_t (s64) it
remains a high positive value instead of sign extending and becoming a
negative again.
Fix this by removing the ternary.
Fixes: b137406d9679 ("drm/bridge: ti-sn65dsi86: If refclk, DP AUX can happen w/out pre-enable")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
drivers/gpu/drm/bridge/ti-sn65dsi86.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index bb0a0e1c6341..45a2969afb2b 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -1042,7 +1042,9 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
pm_runtime_mark_last_busy(pdata->dev);
pm_runtime_put_autosuspend(pdata->dev);
- return ret ? ret : len;
+ if (ret)
+ return ret;
+ return len;
}
static int ti_sn_bridge_parse_dsi_host(struct ti_sn65dsi86 *pdata)
--
2.30.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] drm/bridge: ti-sn65dsi86: fix a ternary type promotion bug
@ 2021-05-18 9:19 ` Dan Carpenter
0 siblings, 0 replies; 6+ messages in thread
From: Dan Carpenter @ 2021-05-18 9:19 UTC (permalink / raw)
To: Andrzej Hajda
Cc: dri-devel, Jonas Karlman, David Airlie, Robert Foss,
Neil Armstrong, kernel-janitors, Douglas Anderson,
Jernej Skrabec, Bjorn Andersson, Laurent Pinchart, linux-kernel
The ti_sn_aux_transfer() function returns ssize_t (signed long). It's
supposed to return negative error codes or the number of bytes
transferred. The "ret" variable is int and the "len" variable is
unsigned int.
The problem is that with a ternary like this, the negative int is first
type promoted to unsigned int to match "len" at this point it is a high
positive value. Then when it is type promoted to ssize_t (s64) it
remains a high positive value instead of sign extending and becoming a
negative again.
Fix this by removing the ternary.
Fixes: b137406d9679 ("drm/bridge: ti-sn65dsi86: If refclk, DP AUX can happen w/out pre-enable")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
drivers/gpu/drm/bridge/ti-sn65dsi86.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index bb0a0e1c6341..45a2969afb2b 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -1042,7 +1042,9 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
pm_runtime_mark_last_busy(pdata->dev);
pm_runtime_put_autosuspend(pdata->dev);
- return ret ? ret : len;
+ if (ret)
+ return ret;
+ return len;
}
static int ti_sn_bridge_parse_dsi_host(struct ti_sn65dsi86 *pdata)
--
2.30.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] drm/bridge: ti-sn65dsi86: fix a ternary type promotion bug
2021-05-18 9:19 ` Dan Carpenter
@ 2021-05-18 13:20 ` Robert Foss
-1 siblings, 0 replies; 6+ messages in thread
From: Robert Foss @ 2021-05-18 13:20 UTC (permalink / raw)
To: Dan Carpenter
Cc: Andrzej Hajda, Neil Armstrong, Laurent Pinchart, Jonas Karlman,
Jernej Skrabec, David Airlie, Daniel Vetter, Bjorn Andersson,
Linus Walleij, Douglas Anderson, dri-devel, linux-kernel,
kernel-janitors
Hey Dan,
Thanks for submitting this.
On Tue, 18 May 2021 at 11:20, Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> The ti_sn_aux_transfer() function returns ssize_t (signed long). It's
> supposed to return negative error codes or the number of bytes
> transferred. The "ret" variable is int and the "len" variable is
> unsigned int.
>
> The problem is that with a ternary like this, the negative int is first
> type promoted to unsigned int to match "len" at this point it is a high
> positive value. Then when it is type promoted to ssize_t (s64) it
> remains a high positive value instead of sign extending and becoming a
> negative again.
>
> Fix this by removing the ternary.
>
> Fixes: b137406d9679 ("drm/bridge: ti-sn65dsi86: If refclk, DP AUX can happen w/out pre-enable")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> drivers/gpu/drm/bridge/ti-sn65dsi86.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index bb0a0e1c6341..45a2969afb2b 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -1042,7 +1042,9 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
> pm_runtime_mark_last_busy(pdata->dev);
> pm_runtime_put_autosuspend(pdata->dev);
>
> - return ret ? ret : len;
> + if (ret)
> + return ret;
> + return len;
> }
>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Applying to drm-misc-fixes.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] drm/bridge: ti-sn65dsi86: fix a ternary type promotion bug
@ 2021-05-18 13:20 ` Robert Foss
0 siblings, 0 replies; 6+ messages in thread
From: Robert Foss @ 2021-05-18 13:20 UTC (permalink / raw)
To: Dan Carpenter
Cc: dri-devel, Jonas Karlman, David Airlie, linux-kernel,
Neil Armstrong, kernel-janitors, Douglas Anderson,
Jernej Skrabec, Bjorn Andersson, Andrzej Hajda, Laurent Pinchart
Hey Dan,
Thanks for submitting this.
On Tue, 18 May 2021 at 11:20, Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> The ti_sn_aux_transfer() function returns ssize_t (signed long). It's
> supposed to return negative error codes or the number of bytes
> transferred. The "ret" variable is int and the "len" variable is
> unsigned int.
>
> The problem is that with a ternary like this, the negative int is first
> type promoted to unsigned int to match "len" at this point it is a high
> positive value. Then when it is type promoted to ssize_t (s64) it
> remains a high positive value instead of sign extending and becoming a
> negative again.
>
> Fix this by removing the ternary.
>
> Fixes: b137406d9679 ("drm/bridge: ti-sn65dsi86: If refclk, DP AUX can happen w/out pre-enable")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> drivers/gpu/drm/bridge/ti-sn65dsi86.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index bb0a0e1c6341..45a2969afb2b 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -1042,7 +1042,9 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
> pm_runtime_mark_last_busy(pdata->dev);
> pm_runtime_put_autosuspend(pdata->dev);
>
> - return ret ? ret : len;
> + if (ret)
> + return ret;
> + return len;
> }
>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Applying to drm-misc-fixes.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] drm/bridge: ti-sn65dsi86: fix a ternary type promotion bug
2021-05-18 13:20 ` Robert Foss
@ 2021-05-18 13:29 ` Robert Foss
-1 siblings, 0 replies; 6+ messages in thread
From: Robert Foss @ 2021-05-18 13:29 UTC (permalink / raw)
To: Dan Carpenter
Cc: Andrzej Hajda, Neil Armstrong, Laurent Pinchart, Jonas Karlman,
Jernej Skrabec, David Airlie, Daniel Vetter, Bjorn Andersson,
Linus Walleij, Douglas Anderson, dri-devel, linux-kernel,
kernel-janitors
Since it fixes drm-misc-next, applied it there instead.
On Tue, 18 May 2021 at 15:20, Robert Foss <robert.foss@linaro.org> wrote:
>
> Hey Dan,
>
> Thanks for submitting this.
>
> On Tue, 18 May 2021 at 11:20, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> >
> > The ti_sn_aux_transfer() function returns ssize_t (signed long). It's
> > supposed to return negative error codes or the number of bytes
> > transferred. The "ret" variable is int and the "len" variable is
> > unsigned int.
> >
> > The problem is that with a ternary like this, the negative int is first
> > type promoted to unsigned int to match "len" at this point it is a high
> > positive value. Then when it is type promoted to ssize_t (s64) it
> > remains a high positive value instead of sign extending and becoming a
> > negative again.
> >
> > Fix this by removing the ternary.
> >
> > Fixes: b137406d9679 ("drm/bridge: ti-sn65dsi86: If refclk, DP AUX can happen w/out pre-enable")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > index bb0a0e1c6341..45a2969afb2b 100644
> > --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > @@ -1042,7 +1042,9 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
> > pm_runtime_mark_last_busy(pdata->dev);
> > pm_runtime_put_autosuspend(pdata->dev);
> >
> > - return ret ? ret : len;
> > + if (ret)
> > + return ret;
> > + return len;
> > }
> >
>
> Reviewed-by: Robert Foss <robert.foss@linaro.org>
>
> Applying to drm-misc-fixes.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] drm/bridge: ti-sn65dsi86: fix a ternary type promotion bug
@ 2021-05-18 13:29 ` Robert Foss
0 siblings, 0 replies; 6+ messages in thread
From: Robert Foss @ 2021-05-18 13:29 UTC (permalink / raw)
To: Dan Carpenter
Cc: dri-devel, Jonas Karlman, David Airlie, linux-kernel,
Neil Armstrong, kernel-janitors, Douglas Anderson,
Jernej Skrabec, Bjorn Andersson, Andrzej Hajda, Laurent Pinchart
Since it fixes drm-misc-next, applied it there instead.
On Tue, 18 May 2021 at 15:20, Robert Foss <robert.foss@linaro.org> wrote:
>
> Hey Dan,
>
> Thanks for submitting this.
>
> On Tue, 18 May 2021 at 11:20, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> >
> > The ti_sn_aux_transfer() function returns ssize_t (signed long). It's
> > supposed to return negative error codes or the number of bytes
> > transferred. The "ret" variable is int and the "len" variable is
> > unsigned int.
> >
> > The problem is that with a ternary like this, the negative int is first
> > type promoted to unsigned int to match "len" at this point it is a high
> > positive value. Then when it is type promoted to ssize_t (s64) it
> > remains a high positive value instead of sign extending and becoming a
> > negative again.
> >
> > Fix this by removing the ternary.
> >
> > Fixes: b137406d9679 ("drm/bridge: ti-sn65dsi86: If refclk, DP AUX can happen w/out pre-enable")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > index bb0a0e1c6341..45a2969afb2b 100644
> > --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > @@ -1042,7 +1042,9 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
> > pm_runtime_mark_last_busy(pdata->dev);
> > pm_runtime_put_autosuspend(pdata->dev);
> >
> > - return ret ? ret : len;
> > + if (ret)
> > + return ret;
> > + return len;
> > }
> >
>
> Reviewed-by: Robert Foss <robert.foss@linaro.org>
>
> Applying to drm-misc-fixes.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-05-18 13:29 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-18 9:19 [PATCH] drm/bridge: ti-sn65dsi86: fix a ternary type promotion bug Dan Carpenter
2021-05-18 9:19 ` Dan Carpenter
2021-05-18 13:20 ` Robert Foss
2021-05-18 13:20 ` Robert Foss
2021-05-18 13:29 ` Robert Foss
2021-05-18 13:29 ` Robert Foss
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.