Re: Bug 205201 - Booting halts if Dawicontrol DC-2976 UW SCSI board installed, unless RAM size limited to 3500M

From: Christoph Hellwig
Date: Thu Nov 21 2019 - 02:29:48 EST


On Sat, Nov 16, 2019 at 08:06:05AM +0100, Christian Zigotzky wrote:
> /*
> * DMA addressing mode.
> *
> * 0 : 32 bit addressing for all chips.
> * 1 : 40 bit addressing when supported by chip.
> * 2 : 64 bit addressing when supported by chip,
> * limited to 16 segments of 4 GB -> 64 GB max.
> */
> #define SYM_CONF_DMA_ADDRESSING_MODE CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE
>
> Cyrus config:
>
> CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE=1
>
> I will configure â0 : 32 bit addressing for all chipsâ for the RC8. Maybe this is the solution.

0 means you are going to do bounce buffering a lot, which seems
generally like a bad idea.

But why are we talking about the sym53c8xx driver now? The last issue
you reported was about video4linux allocations.