[PATCH 1/3] drm/msm/dsi: Fix an error code in msm_dsi_modeset_init()

[PATCH 1/3] drm/msm/dsi: Fix an error code in msm_dsi_modeset_init()

[Dan Carpenter]

Return an error code if msm_dsi_manager_validate_current_config().
Don't return success.

Fixes: 8b03ad30e314 ("drm/msm/dsi: Use one connector for dual DSI mode")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/gpu/drm/msm/dsi/dsi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
index 614dc7f26f2c..75ae3008b68f 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.c
+++ b/drivers/gpu/drm/msm/dsi/dsi.c
@@ -215,8 +215,10 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
 		goto fail;
 	}
 
-	if (!msm_dsi_manager_validate_current_config(msm_dsi->id))
+	if (!msm_dsi_manager_validate_current_config(msm_dsi->id)) {
+		ret = -EINVAL;
 		goto fail;
+	}
 
 	msm_dsi->encoder = encoder;
 
-- 
2.20.1

[PATCH 2/3] drm/msm/dsi: fix off by one in dsi_bus_clk_enable error handling

[Dan Carpenter]

This disables a lock which wasn't enabled and it does not disable
the first lock in the array.

Fixes: 6e0eb52eba9e ("drm/msm/dsi: Parse bus clocks from a list")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index e269df285136..c86b5090fae6 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -451,7 +451,7 @@ static int dsi_bus_clk_enable(struct msm_dsi_host *msm_host)
 
 	return 0;
 err:
-	for (; i > 0; i--)
+	while (--i >= 0)
 		clk_disable_unprepare(msm_host->bus_clks[i]);
 
 	return ret;
-- 
2.20.1

Re: [PATCH 2/3] drm/msm/dsi: fix off by one in dsi_bus_clk_enable error handling

[Dmitry Baryshkov]

On 01/10/2021 15:34, Dan Carpenter wrote:
> This disables a lock which wasn't enabled and it does not disable
> the first lock in the array.
> 
> Fixes: 6e0eb52eba9e ("drm/msm/dsi: Parse bus clocks from a list")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

We should probably switch this to bulk clk api.

> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index e269df285136..c86b5090fae6 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -451,7 +451,7 @@ static int dsi_bus_clk_enable(struct msm_dsi_host *msm_host)
>   
>   	return 0;
>   err:
> -	for (; i > 0; i--)
> +	while (--i >= 0)
>   		clk_disable_unprepare(msm_host->bus_clks[i]);
>   
>   	return ret;
> 


-- 
With best wishes
Dmitry

[PATCH 3/3] drm/msm/dsi: fix signedness bug in msm_dsi_host_cmd_rx()

[Dan Carpenter]

The "msg->tx_len" variable is type size_t so if dsi_cmds2buf_tx()
returns a negative error code that it type promoted to a high positive
value and treat as a success.  The second problem with this code is
that it can return meaningless positive values on error.

Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index c86b5090fae6..42073a562072 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -2133,8 +2133,10 @@ int msm_dsi_host_cmd_rx(struct mipi_dsi_host *host,
 		}
 
 		ret = dsi_cmds2buf_tx(msm_host, msg);
-		if (ret < msg->tx_len) {
+		if (ret < 0 || ret < msg->tx_len) {
 			pr_err("%s: Read cmd Tx failed, %d\n", __func__, ret);
+			if (ret >= 0)
+				ret = -EIO;
 			return ret;
 		}
 
-- 
2.20.1

Re: [PATCH 3/3] drm/msm/dsi: fix signedness bug in msm_dsi_host_cmd_rx()

[Dmitry Baryshkov]

On 01/10/2021 15:36, Dan Carpenter wrote:
> The "msg->tx_len" variable is type size_t so if dsi_cmds2buf_tx()
> returns a negative error code that it type promoted to a high positive
> value and treat as a success.  The second problem with this code is
> that it can return meaningless positive values on error.

It looks to me that this piece of code is not fully correct at all.
dsi_cmds2bus_tx would return the size of DSI packet, not the size of the 
DSI buffer.

Could you please be more specific, which 'meaningless positive values' 
were you receiving?

> 
> Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index c86b5090fae6..42073a562072 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -2133,8 +2133,10 @@ int msm_dsi_host_cmd_rx(struct mipi_dsi_host *host,
>   		}
>   
>   		ret = dsi_cmds2buf_tx(msm_host, msg);
> -		if (ret < msg->tx_len) {
> +		if (ret < 0 || ret < msg->tx_len) {
>   			pr_err("%s: Read cmd Tx failed, %d\n", __func__, ret);
> +			if (ret >= 0)
> +				ret = -EIO;
>   			return ret;
>   		}
>   
> 


-- 
With best wishes
Dmitry

Re: [PATCH 3/3] drm/msm/dsi: fix signedness bug in msm_dsi_host_cmd_rx()

[Dan Carpenter]

On Sat, Oct 02, 2021 at 01:59:56AM +0300, Dmitry Baryshkov wrote:
> On 01/10/2021 15:36, Dan Carpenter wrote:
> > The "msg->tx_len" variable is type size_t so if dsi_cmds2buf_tx()
> > returns a negative error code that it type promoted to a high positive
> > value and treat as a success.  The second problem with this code is
> > that it can return meaningless positive values on error.
> 
> It looks to me that this piece of code is not fully correct at all.
> dsi_cmds2bus_tx would return the size of DSI packet, not the size of the DSI
> buffer.
> 
> Could you please be more specific, which 'meaningless positive values' were
> you receiving?
> 

Sorry, I misread the code.  I thought it returned negatives or the
number of bytes copied.  (This is from static analysis btw).  Anyway,
returning only negatives is a much better way.

I will fix this patch and resend.

regards,
dan carpenter

Re: [PATCH 3/3] drm/msm/dsi: fix signedness bug in msm_dsi_host_cmd_rx()

[Dan Carpenter]

On Sat, Oct 02, 2021 at 01:59:56AM +0300, Dmitry Baryshkov wrote:
> On 01/10/2021 15:36, Dan Carpenter wrote:
> > The "msg->tx_len" variable is type size_t so if dsi_cmds2buf_tx()
> > returns a negative error code that it type promoted to a high positive
> > value and treat as a success.  The second problem with this code is
> > that it can return meaningless positive values on error.
> 
> It looks to me that this piece of code is not fully correct at all.
> dsi_cmds2bus_tx would return the size of DSI packet, not the size of the DSI
> buffer.

Ugh...  I misread what you were saying.  I was thinking I could just
check for negatives.  This sounds like struct_size() thing?

> 
> Could you please be more specific, which 'meaningless positive values' were
> you receiving?
> 

Returning any positive values at this point is a bug.  It's supposed to
return the number of bytes that were recieved.

And there is another bug as well:

drivers/gpu/drm/msm/dsi/dsi_host.c
  1370  static int dsi_cmds2buf_tx(struct msm_dsi_host *msm_host,
  1371                                  const struct mipi_dsi_msg *msg)
  1372  {
  1373          int len, ret;
  1374          int bllp_len = msm_host->mode->hdisplay *
  1375                          dsi_get_bpp(msm_host->format) / 8;
  1376  
  1377          len = dsi_cmd_dma_add(msm_host, msg);
  1378          if (!len) {

The dsi_cmd_dma_add() returns negative error codes so this check should
be "if (len <= 0) {".

  1379                  pr_err("%s: failed to add cmd type = 0x%x\n",
  1380                          __func__,  msg->type);
  1381                  return -EINVAL;
  1382          }
  1383  

I'm not sure about the size of "the DSI packet"  Could you handle this
one and give me a Reported-by tag?  That's probably simpler than another
back and forth on email.

regards,
dan carpenter

Re: [PATCH 1/3] drm/msm/dsi: Fix an error code in msm_dsi_modeset_init()

[Dmitry Baryshkov]

On 01/10/2021 15:33, Dan Carpenter wrote:
> Return an error code if msm_dsi_manager_validate_current_config().
> Don't return success.
> 
> Fixes: 8b03ad30e314 ("drm/msm/dsi: Use one connector for dual DSI mode")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>


> ---
>   drivers/gpu/drm/msm/dsi/dsi.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
> index 614dc7f26f2c..75ae3008b68f 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi.c
> @@ -215,8 +215,10 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
>   		goto fail;
>   	}
>   
> -	if (!msm_dsi_manager_validate_current_config(msm_dsi->id))
> +	if (!msm_dsi_manager_validate_current_config(msm_dsi->id)) {
> +		ret = -EINVAL;
>   		goto fail;
> +	}
>   
>   	msm_dsi->encoder = encoder;
>   
> 


-- 
With best wishes
Dmitry