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

From: Pavel Machek
Date: Wed Mar 04 2020 - 10:13:20 EST


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);
>

Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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