linux-kernel - Re: [PATCH v1 0/2] serial: 8250

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sun, 21 Nov 2021 07:36:32 -0800
From:   Jay Dolan <jay.dolan@...esio.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:SERIAL DRIVERS" <linux-serial@...r.kernel.org>,
        Jiri Slaby <jirislaby@...nel.org>
Subject: Re: [PATCH v1 0/2] serial: 8250_pci: Split Pericom driver



On 11/21/21 2:16 AM, Andy Shevchenko wrote:
> On Sat, Nov 20, 2021 at 11:46 PM Jay Dolan <jay.dolan@...esio.com> wrote:
>> On 11/19/21 6:33 AM, Jay Dolan wrote:
>>> On 11/19/21 12:23 AM, Andy Shevchenko wrote:
>>>> On Thu, Nov 18, 2021 at 10:32:51PM -0800, Jay Dolan wrote:
>>>>> On 11/17/21 6:57 AM, Andy Shevchenko wrote:
> 
>>>>>> Split Pericom driver to a separate module.
>>>>>> While at it, re-enable high baud rates.
>>>>>>
>>>>>> Jay, can you, please, test this on as many hardware as you have?
>>>>>>
>>>>>> The series depends on the fix-series:
>>>>>> https://lore.kernel.org/linux-serial/20211117145502.43645-1-andriy.shevchenko@linux.intel.com/T/#u
>>>>
>>>>> I have my current state here:
>>>>> https://github.com/accesio/linux/blob/split-pericom-driver/drivers/tty/serial/8250/8250_pericom.c
>>>>>
>>>>>
>>>>> * Change port type to UPIO_PORT
>>>>> * Add in pericom_do_startup() because the UPF_MAGIC_MULTIPLIER doesn't
>>>>> stick.
>>>>
>>>> Thanks, I have updated my local tree with these changes.
>>>>
>>>>> When I'm testing baud rates greater than baud_base I'm seeing strange
>>>>> things
>>>>> on the scope.
>>>>
>>>> Can you confirm that there are no issues with the first (fixes) series?
>>> Yes. The fixes series has no issues, and was tested up to baud_base for
>>> both 14 and 24 MHz crystals.
>>>> I have slightly changed your set_divisor() refactoring, it may be that
>>>> issue
>>>> is there.
>>>>
>>>>> Maybe I'm just tired, and it's human error. I should be able
>>>>> to get back to it and get it done on Saturday.
>>>>
>>>> Thank you.
>>
>> Latest code is still here
>> https://github.com/accesio/linux/blob/split-pericom-driver/drivers/tty/serial/8250/8250_pericom.c
>>
>> Changes from last update:
>> * Avoid divide by zero when initializing delta
> 
> Thanks for digging into it. But doesn't it mean that the issue is in
> the fix series as I assumed before?
Yes. It just happens to not get hit at any of the standard baud rates 
that I found in the termbits.h files. So testing didn't find it until 
testing rates greater than what is allowed without the magic multiplier 
flag.
I found it when doing the math on 3000000 because that causes it with 
the 14 MHz crystal.
> 
>> I retested and verified on the scope that speeds are now being set
>> correctly.
>>
>> I have also confirmed that all of the ACCES four port cards in the
>> driver do have the offset fourth port. The item I raised about PCI was a
>> misunderstanding that was all on my end.
> 
> Good to know that is not relevant.
> 
>> Are there any other action items I should be handling?
> 
> I think I have to issue two new iterations of each series and collect
> your formal Tested-by on the second one.
>