From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Date: Wed, 06 May 1998 18:27:16 +0000 Subject: Re: Ultra 1 and Ultra 5 Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ultralinux@vger.kernel.org Date: Wed, 06 May 1998 11:26:04 -0700 From: "Derek R. Pizzagoni" Have there been any modifications to the serial ports in the Ultra 1's and/or Ultra 5's? The older Sparcs had a max of 38400 on the serial ports. Is it the same in the Ultra 1 and in the Ultra 5? The PCI based Ultra machines use the Siemens SAB serial chipsets, which can scream. The SBUS based machines from the first Sparc on use the Zilogs, which also have the potential to scream. Both can scream, when they can use DMA. Unfortunately, even on the Ultra PCI systems, they didn't hook up the DMA lines to the Siemens SAB serial chips at least on the Ultra/AX motherboards, so things don't scream and polled I/O must be used to transfer the bytes in/out of the chip at each interrupt. The decently sized FIFO on the SAB chips helps a bit, but lack of DMA still hurts. Later, David S. Miller davem@dm.cobaltmicro.com