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[192.19.223.250]) by smtp.gmail.com with ESMTPSA id e65-v6sm36169908pfa.90.2018.11.15.09.19.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 15 Nov 2018 09:19:17 -0800 (PST) Subject: Re: [PATCH] serial: 8250: Default SERIAL_OF_PLATFORM to SERIAL_8250 To: Guenter Roeck Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org References: <20181115011125.GA32556@roeck-us.net> <29E7A6C0-7829-4650-93C6-7220FECAA6EF@gmail.com> <20181115053836.GA7606@roeck-us.net> From: Florian Fainelli Openpgp: preference=signencrypt Autocrypt: addr=f.fainelli@gmail.com; keydata= xsBNBFPAG8ABCAC3EO02urEwipgbUNJ1r6oI2Vr/+uE389lSEShN2PmL3MVnzhViSAtrYxeT M0Txqn1tOWoIc4QUl6Ggqf5KP6FoRkCrgMMTnUAINsINYXK+3OLe7HjP10h2jDRX4Ajs4Ghs JrZOBru6rH0YrgAhr6O5gG7NE1jhly+EsOa2MpwOiXO4DE/YKZGuVe6Bh87WqmILs9KvnNrQ PcycQnYKTVpqE95d4M824M5cuRB6D1GrYovCsjA9uxo22kPdOoQRAu5gBBn3AdtALFyQj9DQ KQuc39/i/Kt6XLZ/RsBc6qLs+p+JnEuPJngTSfWvzGjpx0nkwCMi4yBb+xk7Hki4kEslABEB AAHNKEZsb3JpYW4gRmFpbmVsbGkgPGZhaW5lbGxpQGJyb2FkY29tLmNvbT7CwQcEEAECALEF AlPAG9YXCgABv0jL/n0t8VEFmtDa8j7qERo7AN0gFAAAAAAAFgABa2V5LXVzYWdlLW1hc2tA cGdwLmNvbY4wFIAAAAAAIAAHcHJlZmVycmVkLWVtYWlsLWVuY29kaW5nQHBncC5jb21wZ3Bt aW1lCAsJCAcDAgEKAhkBBReAAAAAGRhsZGFwOi8va2V5cy5icm9hZGNvbS5jb20FGwMAAAAD FgIBBR4BAAAABBUICQoACgkQgTG1xCm8ZqD+Dgf9HhhzqvJYIPomNeg+ll7/TbzWb871E+HQ TaufJQFQwLEbgdFSZO2uj4UqfDpCyTwtHTVMJogWt3pCAE1sadeIY8OlT6918ofKIl8AiHj2 BlfL7ASZ5wzkRMt/4TZoinq9O1tPEynb5G6PdZTV3UQtmSGnpt2EOu7KtRJsnThBiXoOO9TJ Asg4vXJ0ZM1y/MPhQlZbPCHQZFe1gaVWBPLGnLyWyeprqgSLWHaGqrUhlfK1sLuJK1bjYDCI NetK0pS4cA4ZJgogr5FrtV64R19zLl02mt/Yj7rAmjC3ZBuwVi3V35kD8Kd4d9QM2apsiILV bzGbtVCSUgvxI+1SsJEm3c7ATQRTwBvBAQgArGvvWip77T4xgJztZp9YRylAcVTC9gtx0Gg6 eYk/EPANGm9TkuGpI++T/Il2H2TjFQNC7eubWohbYj0+6Tmf8nP+VmyobDxPXcMrK7x4xy9o D+Kub2Vf0SXbsM8fL/SqzGbFWZSm73L1L4GZoxvYIz0i7LExYSX2u5YVLaMBaH9HwKt2cvr7 MuTrRHtcbOZImoXT29g2UnoF1uwxYNeRhZY/lRvVkkY0lDipPuDwg3SpfHMtCybPq1uAswQd gEbHzRsEXwCR1OF3pIuGt4I3tSEhH/k1caqi0BlqjbGUOkku44xC2gf1ZU267FBBkdV3yJ/7 KnrJEnkMCYhS3kII9wARAQABwsGBBBgBAgErBQJTwBvCBRsMAAAAwF0gBBkBCAAGBQJTwBvB AAoJEJNgBqiYLw9VDRUIAJaTef6hsUAESnlGDpC+ymL2RZdzAJx9lXjU4hhaFcyhznuyyMJq d3mehmLxsqDRvHDiqyD71w2Bnc838MVZw0pwBPdnb/h9Ocmp0lL/9hwSGWvy4az5lYVyoA9u 14UIzh0YNGu6jr0isd/LJAbHXqwJwWWs3y8PTrpEp68V6lv+aXt5gR03lJEAvIR1Awp4JJ/e Z5y12gQISp0X8xal9YhhDWER92YLYrO2b6Hc2S31lAupzfCw8lmZsP1PRz1GmF/KmDD9J9N/ b8IehhWQqrBQjMjn2K2XkvN75HnAMHKFYfHZR3ZHtK52ZP1crV7THtbtrnPXVDq+vO4QPmdC +SEACgkQgTG1xCm8ZqC6BwgAl3kRh7oozpjpG8jpO8en5CBtTl3G+OpKJK9qbQyzdCsuJ0K1 qe1wZPZbP/Y+VtmqSgnExBzjStt9drjFBK8liPQZalp2sMlS9S7csSy6cMLF1auZubAZEqpm tpXagbtgR12YOo57Reb83F5KhtwwiWdoTpXRTx/nM0cHtjjrImONhP8OzVMmjem/B68NY++/ qt0F5XTsP2zjd+tRLrFh3W4XEcLt1lhYmNmbJR/l6+vVbWAKDAtcbQ8SL2feqbPWV6VDyVKh ya/EEq0xtf84qEB+4/+IjCdOzDD3kDZJo+JBkDnU3LBXw4WCw3QhOXY+VnhOn2EcREN7qdAK w0j9Sw== Message-ID: <27ed27d3-220e-963f-7d2c-64df10421580@gmail.com> Date: Thu, 15 Nov 2018 09:19:14 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <20181115053836.GA7606@roeck-us.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/14/2018 9:38 PM, Guenter Roeck wrote: > On Wed, Nov 14, 2018 at 07:56:47PM -0800, Florian Fainelli wrote: >> >> >> On November 14, 2018 5:11:25 PM PST, Guenter Roeck wrote: >>> On Thu, Nov 01, 2018 at 11:26:06AM -0700, Florian Fainelli wrote: >>>> It is way too easy to miss enabling SERIAL_OF_PLATFORM which would >>>> result in the inability for the kernel to have a valid console >>> device, >>>> which can be seen with: >>>> >>>> Warning: unable to open an initial console. >>>> >>>> and then: >>>> >>>> Run /init as init process >>>> Kernel panic - not syncing: Attempted to kill init! >>> exitcode=0x00000100 >>>> >>>> Since SERIAL_OF_PLATFORM already depends on SERIAL_8250 && OF there >>>> really is no drawback to defaulting this config to the value of >>>> SERIAL_8250. >>>> >>>> Signed-off-by: Florian Fainelli >>>> Signed-off-by: Greg Kroah-Hartman >>> >>> This patch results in situations where CONFIG_SERIAL_OF_PLATFORM is now >>> defined where it was not previously. Example mpc85xx_defconfig. This in >>> turn results in boot failures for those configurations, with an error >>> message of >>> >>> of_serial: probe of e0004500.serial failed with error -22 >>> >>> which wasn't seen before. >> >> Do you know which Device Tree is being used here? The most obvious thing that could be done is to add a !PPC condition but this might be missing other platforms doing their own 8250 registration yet being OF aware (sparc?). >> >>> >>> Not sure if replacing a potential problem with a real one is really an >>> improvement.` >> >> That comment is not particularly helpful though I have an appreciation for when a change breaks things in unexpected ways and how frustrating that can be. > > Actally, never mind. I dropped the test cases. Sorry for the noise. Why? The tests are useful, if I gave you an impression that I was just going to walk away from this issue and not look at it, then that is not happening. What I was objecting to is your qualification of the issue, this is unfortunately not a potential/latent problem, it happens more often than not. The key difference is that most subsystems that are CONFIG_OF aware will get that awareness enabled/active automatically, that is not the case with the 8250 driver, which is why this you can shoot yourself in the foot and end-up with the 8250 driver enabled, but not CONFIG_SERIAL_OF_PLATFORM. I also suspect that for historical reasons powerpc "manually" registers its 8250 ports and does not rely on CONFIG_OF_SERIAL_PLATFORM. I will try to cook a patch as quickly as possible. Thanks -- Florian