Re: [PATCH 2/3] drm:msm: Initial Add Writeback Support

On 2 April 2015 at 19:07, jilaiw@codeaurora.org wrote:

Thanks Emil. Please check the comments embedded and for the rest I will update the code.

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Hi Jilai,

Just a few questions, not really a review as I'm not that familiar with the code.

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+++ b/drivers/gpu/drm/msm/Kconfig @@ -27,6 +27,16 @@ config DRM_MSM_FBDEV support. Note that this support also provide the linux console support on top of the MSM modesetting driver.

+config DRM_MSM_WB

•   bool "Enable writeback support for MSM modesetting driver"
  

•   depends on DRM_MSM
  

•   depends on VIDEO_V4L2
  

•   select VIDEOBUF2_CORE
  

•   default y
  

•   help
  

•     Choose this option if you have a need to support writeback
  

•     connector.
  

Is it worth mentioning which devices/SoCs have such connector ?

If the devices have WB connector, it will be added in the device tree.

I was thinking more about listing a one or two SoCs so that one gets the general idea. Although it might end up more confusing than helpful as more devices become available. Suggestion withdrawn.

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+static struct msm_wb *msm_wb_init(struct platform_device *pdev) +{

•   struct msm_wb *wb = NULL;
  

•   wb = devm_kzalloc(&pdev->dev, sizeof(*wb), GFP_KERNEL);
  

•   if (!wb)
  

•           return ERR_PTR(-ENOMEM);
  

•   wb->pdev = pdev;
  

•   wb->priv_data = devm_kzalloc(&pdev->dev, sizeof(*wb->priv_data),
  

•           GFP_KERNEL);
  

•   if (!wb->priv_data)
  

•           return ERR_PTR(-ENOMEM);
  

•   if (msm_wb_v4l2_init(wb)) {
  

•           pr_err("%s: wb v4l2 init failed\n", __func__);
  

•           return ERR_PTR(-ENODEV);
  

•   }
  

Seems like we're leaking wb and/or wb->priv_data. Add a label and consolidate error handling in there ?

Since the devm_kzalloc function is used here, the system should take care freeing the memory.

You're spot on. Somehow I did not notice that we're using the devm_ version of kzalloc. /me runs in shame :-)

Cheers, Emil