-----Original Message-----
From: linuxppc-dev-bounces+stephen=3Dneuendorffer.name@lists.ozlabs.org

[mailto:linuxppc-dev-

bounces+stephen=3Dneuendorffer.name@lists.ozlabs.org] On Behalf Of Alon

Ziv

Sent: Thursday, November 19, 2009 4:47 AM
To: Arnd Bergmann; linuxppc-dev@lists.ozlabs.org
Subject: RE: Bug in drivers/serial/of_serial.c?
=

Hi,
=

On Monday, November 16, 2009, Arnd wrote:

quoted

quoted

-       { .type =3D "serial", .compatible =3D "ns16550",  .data =3D

(void

*)PORT_16550, },

quoted

quoted

+       { .type =3D "serial", .compatible =3D "ns16550",  .data =3D

(void

*)PORT_16550A, },

quoted

Does not seem logical. If the device claims compatibility with

ns16550, we should

quoted

not automatically assume it's an ns16550a. Why not add another line

for

quoted

=

Unfortunately, there is no way to change what the device claims--it's
encoded into the OpenFirmware tree by the EDK tools.
And, in any case, the device is actually not lying: it _is_ compatible
with NS16550--just with a non-buggy one.  Unfortunately the kernel
driver for 8250-class UARTs makes the conservative choice to assume

any

16550 is one of the (early, buggy) revisions where the FIFO was
non-functional; any 16550 with working UART is classed as a 16550A.

Definitely changing what is generated by EDK seems to make sense here...

Steve


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