[U-Boot] Maximum size of u-boot.imx for TBS2910 board

[Tom Rini <trini@konsulko.com>]

On Fri, Nov 22, 2019 at 02:38:51AM +0100, Marek Vasut wrote:
> On 11/22/19 2:30 AM, Tom Rini wrote:
> > On Fri, Nov 22, 2019 at 02:27:16AM +0100, Marek Vasut wrote:
> >> On 11/22/19 1:32 AM, Tom Rini wrote:
> >>> On Fri, Nov 22, 2019 at 01:23:56AM +0100, Marek Vasut wrote:
> >>>> On 11/21/19 11:45 PM, Tom Rini wrote:
> >>>>> On Thu, Nov 21, 2019 at 11:01:43PM +0100, Marek Vasut wrote:
> >>>>>> On 11/21/19 10:59 PM, Heinrich Schuchardt wrote:
> >>>>>>> On 11/21/19 9:12 PM, Tom Rini wrote:
> >>>>>>>> On Thu, Nov 21, 2019 at 09:09:29PM +0100, Heinrich Schuchardt wrote:
> >>>>>>>>> Hello Soeren,
> >>>>>>>>>
> >>>>>>>>> when trying to add support for function key support in the USB keyboard
> >>>>>>>>> driver u-boot.imx for the TBS2910 surpassed the maximum size for
> >>>>>>>>> u-boot.imx.
> >>>>>>>>> https://travis-ci.org/marex/u-boot-usb/builds/614059004
> >>>>>>>>>
> >>>>>>>>> Do you remember why on the TBS2910 board this size is limited to
> >>>>>>>>> 0x5fc00? Other i.MX6 boards like the Wandboard allow a much larger
> >>>>>>>>> u-boot.imx.
> >>>>>>>>>
> >>>>>>>>> The limit is defined here:
> >>>>>>>>> include/configs/tbs2910.h:80:
> >>>>>>>>> #define CONFIG_BOARD_SIZE_LIMIT 392192 /* (CONFIG_ENV_OFFSET - 1024) */
> >>>>>>>>>
> >>>>>>>>> Could the value CONFIG_ENV_OFFSET=0x60000 be enlarged?
> >>>>>>>>>
> >>>>>>>>> Many i.MX6 defconfigs use CONFIG_ENV_OFFSET=0xC0000.
> >>>>>>>>
> >>>>>>>> The nature of these boards (aimed at end users) means that we just do
> >>>>>>>> not want to / cannot really move the stored environment.  Thanks!
> >>>>>>>
> >>>>>>> Another possibility would be to reduce the image size by using
> >>>>>>> CONFIG_REGEX=n which should be fine for a board with only one supported
> >>>>>>> network interface.
> >>>>>>
> >>>>>> But the board was fine before your patchset got applied and this is just
> >>>>>> a workaround for added bloat, which reduces functionality. I dislike
> >>>>>> trading functionality for bloat, sorry.
> >>>>>
> >>>>> One persons "bloat" is another persons "added functionality".
> >>>>
> >>>> It would seem this board did not suffer from the lack of this particular
> >>>> functionality before, and I would say that a board should stay at least
> >>>> as functional as it was when it was added. Replacing existing
> >>>> functionality with random unrelated new one makes no sense.
> >>>
> >>> Was it tho?  I believe we're talking about supporting some additional
> >>> keys via USB keyboard.  This board does in fact expect users to be at
> >>> the U-Boot prompt via USB keyboard.
> >>
> >> How did you reach this conclusion ? It seems to be some sort of devkit.
> > 
> > It came up in one of the previous threads about this board and what we
> > can / cannot do about the size constraint and the board maintainers
> > unhappiness about the overall size growth and broken releases (until
> > size growth became a link error on the platform).
> 
> Link please ? It sounds relevant to this thread too.

https://lists.denx.de/pipermail/u-boot/2019-April/365297.html

> >>>>> I believe
> >>>>> the specific changes in question that once again push this board over
> >>>>> fall in to that grey area.  Whatever size-trimming the board maintainer
> >>>>> is fine with next is fine with me, but needs to get ack'd by someone.
> >>>>
> >>>> Or, the other option is, make these new extra features configurable and
> >>>> disable them on this board. And so there should be no size problem.
> >>>
> >>> But that direction leads to saying every slight bit of functionality
> >>> requires a new Kconfig entry.  Some levels of bugfixes as well.
> >>
> >> The other option is, we will sink in bloat and suffer endless size problems.
> > 
> > Yes, it is a hard balancing act.  Stepping back, perhaps a "minimal" or
> > "complete" choice for USB HID devices would make sense and allow us
> > further areas to reduce size, on the minimal portion.
> 
> Or maybe there is a way to help compiler optimize that USB key code
> handling better.

Perhaps.  But my point is that every little functional change or
enhancement does not need a Kconfig option.

-- 
Tom
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