Messages in this thread | | | From | Zang Roy-r61911 <> | Subject | RE: [PATCH/2.6.17-rc4 8/10] Add tsi108 8250 serial support | Date | Thu, 15 Jun 2006 13:13:52 +0800 |
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> > On May 17, 2006, at 5:14 AM, Zang Roy-r61911 wrote: > > > > > This patch contains changes to the serial device driver > specific for > > > integrated serial port in Tsi108 Host Bridge. > > There's no explaination about why this is required. What is > the problem? > Which changes relate directly to this problem and which > changes are related to fixing some other issue not related to > the errata? >
More detailed explanation:
This patch addresses two differences in the Tsi108/109 UART behavior from the standard one.
1. Check for UART_IER_UUE bit in the autoconfig routine. This section of autoconfig is excluded for Tsi108/109 because bits 7 and 6 are reserved for internal use. They are R/W bits. In addition to incorrect identification, changing these bits (from 00) will make Tsi108/109 UART non-functional.
2. ERRATA. Reading the UART's Interrupt Identification Register (IIR) clears the Transmit Holding Register Empty (THRE) and Transmit buffer Empty (TEMP) interrupts even if they are not enabled in the Interrupt Enable Register (IER). This leads to loss of the interrupts. Interrupts are not cleared when reading UART registers as 32-bit word. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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