Hello Sören,
wp-inverted solves the practical problem indeed, and fools the driver
into thinking that the card has an inverted write protection sensor, and
the logic zero that it finds in the hardware register means that the
card isn't write protected.
I'm insisting on this patch, because I think that the device tree should
describe the hardware as it is, and not fool the driver into behaving
the way we want it to. These tricks always bite back later on.
Regards,
Eli
On 04/03/14 21:26, Sören Brinkmann wrote:
Hi Eli,
On Sun, 2014-03-02 at 01:20PM +0200, Eli Billauer wrote:
The write protection signal is absent on a board based upon Xilinx' Zynq
processor ("ZyBo"). This leads the kernel to think that the MicroSD card is
write protected, and causes a kernel panic during boot, as root fails to
mount RW.
I talked to some people here at Xilinx. According to them, you have the
option to pin out the WP signal, which would mean the board needs to
tie/connect the signal properly. Or, if you select to not pin out the WP
signal, it should be tied to 0 within the chip.
Currently, I have some doubts that is the case, since Mike reported the
same issue, but would you mind double checking?
In theory the signal should default to logic zero which would at most
require to add the, already existing, 'wp-inverted' quirk when using
micro-sd on Zynq.
Thanks,
Sören
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