Re: [PATCH 4.19 04/87] drm/msm: Set dma maximum segment size for mdss

On Wed, Mar 04, 2020 at 04:13:16PM +0100, Pavel Machek wrote:

Hi!

...

Turning on CONFIG_DMA_API_DEBUG_SG results in the following error:

[ 12.078665] msm ae00000.mdss: DMA-API: mapping sg segment longer than device claims to support [len=3526656] [max=65536] [ 12.089870] WARNING: CPU: 6 PID: 334 at /mnt/host/source/src/third_party/kernel/v4.19/kernel/dma/debug.c:1301 debug_dma_map_sg+0x1dc/0x318

This one leaks resources in the (very improbable) case of error; it needs to goto cleanup instead of simply returning.

...

+++ b/drivers/gpu/drm/msm/msm_drv.c @@ -492,6 +492,14 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv) if (ret) goto err_msm_uninit;

• if (!dev->dma_parms) {

• dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
  

• 			      GFP_KERNEL);
  

• if (!dev->dma_parms)
  

• 	return -ENOMEM;
  

• }
• dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
• msm_gem_shrinker_init(ddev);

Can you submit a patch to fix it?

thanks,

greg k-h