[U-Boot] [PATCH v2 1/2] usb: composite: fix possible alignment issues

Heinrich Schuchardt xypron.glpk at gmx.de
Fri Nov 22 17:32:13 UTC 2019

On 11/22/19 1:14 PM, Marek Vasut wrote:
> On 11/22/19 12:58 PM, Heinrich Schuchardt wrote:
>> On 11/22/19 8:47 AM, Simon Goldschmidt wrote:
>>> On Fri, Nov 22, 2019 at 7:50 AM Heinrich Schuchardt
>>> <xypron.glpk at gmx.de> wrote:
>>>> On 11/22/19 1:25 AM, Marek Vasut wrote:
>>>>> On 11/21/19 10:15 PM, Simon Goldschmidt wrote:
>>>>>> Since upgrading to gcc9, warnings are issued:
>>>>>> "taking address of packed member of ‘...’ may result in an unaligned
>>>>>> pointer value"
>>>>>> Fix this by converting two functions to use unaligned access since
>>>>>> packed
>>>>>> structures may be on an unaligned address, depending on USB hardware.
>>>>>> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
>>>>> Applied both, thanks.
>>>> With these two patches applied to origin/master GCC 9.2.1 does not
>>>> produce warnings anymore but for tbs2910_defconfig:
>>>> u-boot.imx exceeds file size limit:
>>>>      limit:  0x5fc00 bytes
>>>>      actual: 0x60c00 bytes
>>>>      excess: 0x1000 bytes
>>>> make: *** [Makefile:1159: u-boot.imx] Error 1
>>>> make: *** Deleting file 'u-boot.imx'
>>>> So irrespective of my patches for the USB keyboard we need to address
>>>> the size limit on TBS2910.
>>> Is that due to my cleanup patches? Can you compare the size by compiling
>>> without them? That should work if you leave away the -Werror switch.
>>> Regards,
>>> Simon
>> GCC 9.2.1 without your patches but with -Wno-address-of-packed-member:
>> u-boot.imx exceeds file size limit:
>>    limit:  0x5fc00 bytes
>>    actual: 0x60c00 bytes
>>    excess: 0x1000 bytes
> I see, so you have additional options added to the build which trigger
> the size issue. It would be nice to mention that up front. Do you use
> any other extra options ?

Dear Marek,

Simon asked me to determine if origin/master exceeds the u-boot.imx size
limit when compiled without his patches. The only way to do so is to
suppress the build warnings.

-Wno-address-of-packed-member is the only option I added to
origin/master. This option suppresses the build error that we get
without Simon's patches.

The only other difference between Gitlab CI and my setup is that I use
GCC 9.2.1 (arm-linux-gnueabihf-gcc on Debian Bullseye).

These are the sizes of u-boot.bin:

390080 bytes with Simon's patches
390080 bytes with Simon's patches + -Wno-address-of-packed-member
390064 bytes origin/master + -Wno-address-of-packed-member
386248 bytes with Simon's patches + CONFIG_REGEX=n
390024 bytes with Simon patches +
"usb: kbd: simplify coding for arrow keys"
390440 bytes with Simon patches + all my USB keyboard patches

So I will add a CONFIG option to my "usb: kbd: implement special keys"
patch to avoid the code increase.

With CONFIG_REGEX=n the image fits into the current board limit in all

Soeren could you, please, evaluate if this configuration works with your
board. It should only be relevant if multiple network interfaces are
supported by U-Boot.

Best regards


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