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

From: Christoph Hellwig <[email-masked]>
Date: Thu, 21 Nov 2019 08:29:43 +0100

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 “0 : 32 bit addressing for all chips” 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.