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Date:   Fri, 21 Aug 2020 16:34:21 -0400
From:   Sasha Levin <sashal@kernel.org>
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Gal Pressman <galpress@amazon.com>,
        Shadi Ammouri <sammouri@amazon.com>,
        Yossi Leybovich <sleybo@amazon.com>, linux-rdma@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 5.8 55/62] RDMA/efa: Add EFA 0xefa1 PCI ID
Message-ID: <20200821203421.GD8670@sasha-vm>
References: <20200821161423.347071-1-sashal@kernel.org>
 <20200821161423.347071-55-sashal@kernel.org>
 <20200821194036.GB2811093@nvidia.com>
 <20200821195322.GC8670@sasha-vm>
 <20200821201952.GB2811871@nvidia.com>
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On Fri, Aug 21, 2020 at 05:19:52PM -0300, Jason Gunthorpe wrote:
>On Fri, Aug 21, 2020 at 03:53:22PM -0400, Sasha Levin wrote:
>> On Fri, Aug 21, 2020 at 04:40:36PM -0300, Jason Gunthorpe wrote:
>> > On Fri, Aug 21, 2020 at 12:14:16PM -0400, Sasha Levin wrote:
>> > > From: Gal Pressman <galpress@amazon.com>
>> > >
>> > > [ Upstream commit d4f9cb5c5b224dca3ff752c1bb854250bf114944 ]
>> > >
>> > > Add support for 0xefa1 devices.
>> > >
>> > > Link: https://lore.kernel.org/r/20200722140312.3651-5-galpress@amazon.com
>> > > Reviewed-by: Shadi Ammouri <sammouri@amazon.com>
>> > > Reviewed-by: Yossi Leybovich <sleybo@amazon.com>
>> > > Signed-off-by: Gal Pressman <galpress@amazon.com>
>> > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
>> > > Signed-off-by: Sasha Levin <sashal@kernel.org>
>> > >  drivers/infiniband/hw/efa/efa_main.c | 6 ++++--
>> > >  1 file changed, 4 insertions(+), 2 deletions(-)
>> >
>> > Wait, what? Why is this being autosel'd?
>>
>> Stable trees try to pick up device enablement patches (such as patches
>> that add PCI IDs). I suppose that AUTOSEL get pretty eager to grab
>> those.
>
>Is it so common that old drivers will work with new HW with just a
>PCI_ID update?
>
>I would have guessed that is the minority situation

So keep in mind that a lot of it is not brand new HW, but rather same
HW repackaged by a different vendor, or HW that received minor tweaks
but where the old driver still works.

I suppose it's more common in the USB ID world these days, so I guess
I'll give PCI IDs a closer look next time.

-- 
Thanks,
Sasha