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Message-ID: <5882d4c4-8ab9-0d33-91eb-ac4cfcd189b6@hisilicon.com>
Date: Wed, 23 Feb 2022 11:30:18 +0800
From: Zhou Wang <wangzhou1@...ilicon.com>
To: Jie Hai <haijie1@...wei.com>, <vkoul@...nel.org>
CC: <dmaengine@...r.kernel.org>, <linux-kernel@...r.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@...wei.com>
Thanks for fixing it.
Acked-by: Zhou Wang <wangzhou1@...ilicon.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
>
>
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