Re: [PATCH] drm/etnaviv: fix DMA direction handling for cached read/write buffers

Sui Jingfeng <sui.jingfeng@xxxxxxxxx> · Thu, 8 Feb 2024 14:19:32 +0800

Hi,

On 2024/1/29 18:29, Daniel Stone wrote:
Hi Lucas,

On Fri, 26 Jan 2024 at 17:00, Lucas Stach <l.stach@xxxxxxxxxxxxxx> wrote:
The dma sync operation needs to be done with DMA_BIDIRECTIONAL when
the BO is prepared for both read and write operations. With the
current inverted if ladder it would only be synced for DMA_FROM_DEVICE.

[...]

  static inline enum dma_data_direction etnaviv_op_to_dma_dir(u32 op)
  {
-       if (op & ETNA_PREP_READ)
+       if (op & (ETNA_PREP_READ | ETNA_PREP_WRITE))
+               return DMA_BIDIRECTIONAL;
This test will always be true for _either_ read or write.

Haha, I think it should be"if ((op & ETNA_PREP_READ) && (op & ETNA_PREP_WRITE))"

Cheers,
Daniel