Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI driver

From	Heikki Krogerus <heikki.krogerus@linux.intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI driver
Date	2016-05-04 15:20 +0200
Message-ID	<rv4SC-4va-13@gated-at.bofh.it> (permalink)
References	<rsy0O-22y-3@gated-at.bofh.it> <rsy0O-22y-17@gated-at.bofh.it> <rv1rJ-1lo-15@gated-at.bofh.it> <rv1Bo-1pk-5@gated-at.bofh.it> <rv1L5-1t3-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

Hi Bryan,

On Wed, May 04, 2016 at 10:51:17AM +0100, Bryan O'Donoghue wrote:
> On Wed, 2016-05-04 at 12:42 +0300, Andy Shevchenko wrote:
> > On Wed, May 4, 2016 at 12:31 PM, Bryan O'Donoghue
> > <pure.logic@nexus-software.ie> wrote:
> > > Andy,
> > > 
> > > If you are going to start removing working PCI devices from the PCI
> > > config table in favour of a shim in SERIAL_8250_LPSS then the very
> > > minimum should be some sort of dependency link between
> > > SERIAL_8250_LPSS
> > > and CONFIG_SERIAL_8250_PCI in kconfig.
> > > 
> > > A user could reasonably read the QRK datasheet - switch on
> > > CONFIG_SERIAL_8250_PCI and then wonder why no console output
> > > happened
> > > on boot. S/he shouldn't have to know that devices were moved from
> > > the
> > > PCI driver to an LPSS shim driver or that the 8250_lpss driver now
> > > needs to be selected instead of the intuitively correct 8250_pci
> > > driver.
> > 
> > That is taken care of since default is set to SERIAL_8250 (you even
> > don't need to have PCI driver enabled!).
> > Doesn't work for you?
> 
> The default may be set to SERIAL_8250 but, without the QRK specific
> entry in 8250_pci.c you won't get console output.
> 
> So if you are going to remove the QRK entry from 8250_pci.c and stuff
> it into 8250_lpss.c then 8250_lpss needs to be selected by
> CONFIG_SERIAL_8250_PCI.
> 
> Otherwise the person doing the config needs to know that stuff was
> moved from one file to another - even though it's a PCI device (not an
> LPSS/ACPI enumerated device) - which seems like an unreasonable level
> of knowledge to assume on the part of the user.

The only way the user get's to de-select CONFIG_SERIAL_8250_PCI or
CONFIG_SERIAL_8250_LPSS is if S/he also selects CONFIG_EXPERT, and if
S/he does that then we can assume S/he has the knowledge.

I'm against binding these separated drivers to CONFIG_SERIAL_8250_PCI
because doing that will very fast mean that we also remove the
possibility to de-select CONFIG_SERIAL_8250_PCI when only, for
example, CONFIG_SERIAL_8250_LPSS was wanted.


Thanks,

-- 
heikki

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Bryan O'Donoghue <pure.logic@nexus-software.ie> - 2016-05-04 11:40 +0200
  Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI driver Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-05-04 11:50 +0200
    Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Bryan O'Donoghue <pure.logic@nexus-software.ie> - 2016-05-04 12:00 +0200
      Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI driver Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-05-04 12:10 +0200
        Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Bryan O'Donoghue <pure.logic@nexus-software.ie> - 2016-05-04 13:10 +0200
          Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2016-05-04 13:20 +0200
            Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Bryan O'Donoghue <pure.logic@nexus-software.ie> - 2016-05-04 16:40 +0200
              Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2016-05-04 17:00 +0200
            Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Bryan O'Donoghue <pure.logic@nexus-software.ie> - 2016-05-04 17:00 +0200
              Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2016-05-04 19:50 +0200
                Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Bryan O'Donoghue <pure.logic@nexus-software.ie> - 2016-05-05 19:50 +0200
                Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2016-05-06 12:40 +0200
      Re: [PATCH v3 09/11] serial: 8250_lpss: move Quark code from PCI  driver Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-05-04 15:20 +0200

csiph-web