Re: [PATCH] drm/dsi: Fix improper use of mipi_dsi_device_transfer() return value

[Sean Paul]

On Mon, Jan 15, 2018 at 10:12:24AM +0100, Andrzej Hajda wrote:
> On 12.01.2018 15:48, Philippe Cornu wrote:
> > The function mipi_dsi_device_transfer() returns the number of transmitted
> > or received bytes on success or a negative error code on failure.
> >
> > The functions mipi_dsi_shutdown_peripheral(), mipi_dsi_turn_on_peripheral() &
> > mipi_dsi_set_maximum_return_packet_size() use improperly this returned
> > value in case of success: 0 should be returned instead of the number of
> > transmitted bytes.
> >
> > Signed-off-by: Philippe Cornu <philippe.cornu@xxxxxx>
> 
> I guess, the best would be to create and use some helper similar to
> PTR_ERR_OR_ZERO,
> but this is also OK.
> 
> Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>

Applied to drm-misc-next. Thanks for the patch and review

Sean

> 
>  --
> Regards
> Andrzej
> 
> > ---
> >  drivers/gpu/drm/drm_mipi_dsi.c | 9 ++++++---
> >  1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
> > index 4b47226b90d4..bc73b7f5b9fc 100644
> > --- a/drivers/gpu/drm/drm_mipi_dsi.c
> > +++ b/drivers/gpu/drm/drm_mipi_dsi.c
> > @@ -498,8 +498,9 @@ int mipi_dsi_shutdown_peripheral(struct mipi_dsi_device *dsi)
> >  		.tx_buf = (u8 [2]) { 0, 0 },
> >  		.tx_len = 2,
> >  	};
> > +	int ret = mipi_dsi_device_transfer(dsi, &msg);
> >  
> > -	return mipi_dsi_device_transfer(dsi, &msg);
> > +	return (ret < 0) ? ret : 0;
> >  }
> >  EXPORT_SYMBOL(mipi_dsi_shutdown_peripheral);
> >  
> > @@ -517,8 +518,9 @@ int mipi_dsi_turn_on_peripheral(struct mipi_dsi_device *dsi)
> >  		.tx_buf = (u8 [2]) { 0, 0 },
> >  		.tx_len = 2,
> >  	};
> > +	int ret = mipi_dsi_device_transfer(dsi, &msg);
> >  
> > -	return mipi_dsi_device_transfer(dsi, &msg);
> > +	return (ret < 0) ? ret : 0;
> >  }
> >  EXPORT_SYMBOL(mipi_dsi_turn_on_peripheral);
> >  
> > @@ -541,8 +543,9 @@ int mipi_dsi_set_maximum_return_packet_size(struct mipi_dsi_device *dsi,
> >  		.tx_len = sizeof(tx),
> >  		.tx_buf = tx,
> >  	};
> > +	int ret = mipi_dsi_device_transfer(dsi, &msg);
> >  
> > -	return mipi_dsi_device_transfer(dsi, &msg);
> > +	return (ret < 0) ? ret : 0;
> >  }
> >  EXPORT_SYMBOL(mipi_dsi_set_maximum_return_packet_size);
> >  
> 
> 

-- 
Sean Paul, Software Engineer, Google / Chromium OS