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

[Tom Rini <trini@konsulko.com>]

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).

> >>> 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.

-- 
Tom
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