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

[Robin Murphy <robin.murphy@arm.com>]

On 21/11/2019 12:21 pm, Christian Zigotzky wrote:
> On 21 November 2019 at 01:16 pm, Christian Zigotzky wrote:
>> On 21 November 2019 at 08:29 am, Christoph Hellwig wrote:
>>> 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.
>>>
>> Both drivers have the same problem. They don't work if we have more 
>> than 3.5GB RAM. I try to find a solution until you have a good 
>> solution. I have already a solution for V4L but I still need one for 
>> the sym53c8xx driver.
> OK, you mean that "0" is a bad idea but maybe it works until you have a 
> solution. ;-)

Is this on the same machine with the funny non-power-of-two bus_dma_mask 
as your other report? If so, does Nicolas' latest patch[1] help at all?

Robin.

[1] 
https://lore.kernel.org/linux-iommu/20191121092646.8449-1-nsaenzjulienne@suse.de/T/#u