RE: [PATCH] dmaengine: hisi_dma: fix MSI allocate fail when reload hisi_dma

[haijie <haijie1@huawei.com>]

hello, kindly ping for review status. :)

-----Original Message-----
From: Wangzhou (B) 
Sent: Wednesday, February 23, 2022 11:30 AM
To: haijie <haijie1@huawei.com>; vkoul@kernel.org
Cc: dmaengine@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dmaengine: hisi_dma: fix MSI allocate fail when reload hisi_dma

> Remove the loaded hisi_dma driver and reload it, the driver fails to 
> work properly. The following error is reported in the kernel log:
> 
> [ 1475.597609] hisi_dma 0000:7b:00.0: Failed to allocate MSI vectors!
> [ 1475.604915] hisi_dma: probe of 0000:7b:00.0 failed with error -28
> 
> As noted in "The MSI Driver Guide HOWTO"[1], the number of MSI 
> interrupt must be a power of two. The Kunpeng DMA driver allocates 30 
> MSI interrupts. As a result, no space left on device is reported when 
> the driver is reloaded and allocates interrupt vectors from the 
> interrupt domain.
> 
> This patch changes the number of interrupt vectors allocated by 
> hisi_dma driver to 32 to avoid this problem.
> 
> [1] https://www.kernel.org/doc/html/latest/PCI/msi-howto.html
> 
> Fixes: e9f08b65250d ("dmaengine: hisilicon: Add Kunpeng DMA engine 
> support")
> 
> Signed-off-by: Jie Hai <haijie1@huawei.com>

Thanks for fixing it.

Acked-by: Zhou Wang <wangzhou1@hisilicon.com>

Best,
Zhou

> ---
>  drivers/dma/hisi_dma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/hisi_dma.c b/drivers/dma/hisi_dma.c index 
> 97c87a7cba87..43817ced3a3e 100644
> --- a/drivers/dma/hisi_dma.c
> +++ b/drivers/dma/hisi_dma.c
> @@ -30,7 +30,7 @@
>  #define HISI_DMA_MODE			0x217c
>  #define HISI_DMA_OFFSET			0x100
>  
> -#define HISI_DMA_MSI_NUM		30
> +#define HISI_DMA_MSI_NUM		32
>  #define HISI_DMA_CHAN_NUM		30
>  #define HISI_DMA_Q_DEPTH_VAL		1024
>  
>