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Subject: Re: [PATCH AUTOSEL 5.8 55/62] RDMA/efa: Add EFA 0xefa1 PCI ID
To:     Sasha Levin <sashal@kernel.org>, Jason Gunthorpe <jgg@nvidia.com>
CC:     <linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>,
        Shadi Ammouri <sammouri@amazon.com>,
        Yossi Leybovich <sleybo@amazon.com>,
        <linux-rdma@vger.kernel.org>
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> <20200821203421.GD8670@sasha-vm>
From:   Gal Pressman <galpress@amazon.com>
Message-ID: <ff34f370-66c2-6c2d-89ea-5ebaf965b37f@amazon.com>
Date:   Sun, 23 Aug 2020 09:43:15 +0300
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On 21/08/2020 23:34, Sasha Levin wrote:
> 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.

FWIW, Jason is right, this patch will break without taking the rest of the series:
https://lore.kernel.org/linux-rdma/20200722140312.3651-1-galpress@amazon.com/

Thanks Jason and Sasha.