On Tue, 2015-11-24 at 11:12 -0500, Timur Tabi wrote:

 On Tue, Nov 24, 2015 at 1:27 AM, Dongsheng Wang
[off-list ref] wrote:

quoted

@@ -1697,6 +1700,9 @@ static int fsl_diu_probe(struct platform_device

*pdev)
        unsigned int i;
        int ret;

+       if (!diu_ops.set_pixel_clock)
+               return -ENODEV;
+
        data = dmam_alloc_coherent(&pdev->dev, sizeof(struct
fsl_diu_data),
                                   &dma_addr, GFP_DMA | __GFP_ZERO);
        if (!data)

This doesn't make any sense.  If set_pixel_clock() is not defined,
then the whole driver aborts the probe.

That's what this patch is trying to accomplish.  Currently it crashes instead.

  When could that ever happen?
If the platform code does not exist, then don't let the driver be
probed.

How do you propose to accomplish that other than with such a check?

-Scott