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Date:   Sun, 23 Jan 2022 16:04:11 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Oded Gabbay <ogabbay@kernel.org>
Cc:     Cai Huoqing <cai.huoqing@linux.dev>, Arnd Bergmann <arnd@arndb.de>,
        "Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] habanalabs: Remove unused enum member DMA_SRAM_TO_SRAM
Message-ID: <Ye1ua3ixuSfdhiRc@kroah.com>
References: <20220111114724.7987-1-cai.huoqing@linux.dev>
 <CAFCwf10GWN_hdsvUf+7dFFK=CwjuGxXPZZt8c2dkVOb24VZxcQ@mail.gmail.com>
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On Sun, Jan 23, 2022 at 04:43:15PM +0200, Oded Gabbay wrote:
> On Tue, Jan 11, 2022 at 1:47 PM Cai Huoqing <cai.huoqing@linux.dev> wrote:
> >
> > The driver don't support the SRAM-to-SRAM translation of DMA,
> > so remove 'DMA_SRAM_TO_SRAM'.
> >
> > Signed-off-by: Cai Huoqing <cai.huoqing@linux.dev>
> > ---
> >  drivers/misc/habanalabs/include/goya/goya_packets.h | 1 -
> >  1 file changed, 1 deletion(-)
> >
> > diff --git a/drivers/misc/habanalabs/include/goya/goya_packets.h b/drivers/misc/habanalabs/include/goya/goya_packets.h
> > index ef54bad20509..25fbebdc6143 100644
> > --- a/drivers/misc/habanalabs/include/goya/goya_packets.h
> > +++ b/drivers/misc/habanalabs/include/goya/goya_packets.h
> > @@ -36,7 +36,6 @@ enum goya_dma_direction {
> >         DMA_SRAM_TO_HOST,
> >         DMA_DRAM_TO_HOST,
> >         DMA_DRAM_TO_DRAM,
> > -       DMA_SRAM_TO_SRAM,
> >         DMA_ENUM_MAX
> >  };
> >
> > --
> > 2.25.1
> >
> 
> This is a general spec file in our s/w stack, and therefore a change
> in it in the driver will cause our driver to be out of sync with our
> user-space stack. i.e. the value of DMA_ENUM_MAX will be different in
> the driver and in the user-space stack. I don't know if there will be
> any consequences but I prefer not to risk it.

If this is synced to userspace, shouldn't it be in a uapi file with a
specific value associated with it?

thanks,

greg k-h