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Date:      Fri, 05 Jun 1998 19:43:47 +0800
From:      Shiaw Yi Hsieh <syhsieh@ali.com.tw>
To:        freebsd-questions@FreeBSD.ORG, johnson@ali.com.tw
Subject:   FreeBSD 2.2.5 AND 2.2.6 can not found serial port at Acer labs. M5135
Message-ID:  <3577D9F3.80754AD7@ali.com.tw>

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Dear sir,
Several month ago, one of our customers name Iwill feedback one
question:
FreeBSD 2.2.5 can not found UART port at Iwill motherboard (use Acer
labs. M5135). This parts is use Intel new technology name--serial IRQ.
and did not found any problem in the other parts such as M5113,M5123 AND
M1543.
And our R&D people made much effort to study how FreeBSD can not found
UART  and Tape out a new version to fixed this issue(for 2.2.5).
But after we get the new chip we still have got the following issue:

1. FreeBSD  boot from CD-ROM     PASS
2. FreeBSD  boot from HDD            PASS
3 FreeBSD  boot from FDD              FAIL

After we studied the different between boot from CD-ROM,HDD AND FDD
we found the different is in the command  and command recovery time when
FreeBSD polling UART's IRQ(read IIR register 2fa,3fa,2ea,3ea). The
recovery time of CD-ROM,HDD is around several us but  FDD command
recovery time only 2us. would it possible last the FDD commend recovery
time to over 10us?
Maybe Serial IRQ will take more time when set IIR register and read 8259
to get the status, so we recommend OS polling or read those IIR register
it is better to last the recovery time to get the 8259 IRQ status.
Another issue is read 8259 IRQ status method, in the parallel IRQ  you
can read from edge or level but NEW serial IRQ our chip M5135 only have
got a pulse and not the level. Maybe this is why FreeBSD can not found
UART.
Our new chip had been option to change the IRQ from pulse to level, but
in FDD boot still have this issue. Do you have any comments? And FreeBSD
test have been put in our chip verify item, so if you release new
version, please mail to us for testting.

If you have any comments please contact me: johnson@ali.com.tw

Thanks

JOHNSON CHEN / MANAGER   Acer Labs. Inc


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