Re: [PATCH] libata: increase LBA48 max sectors to 65535

[Tejun Heo <htejun@gmail.com>]

Jens Axboe wrote:
> On Wed, Feb 15 2006, Tejun Heo wrote:
> 
>>max_hw_sectors/max_sectors separation patch made into the tree,
>>increase max_sectors to its hardware limit.
>>
>>Signed-off-by: Tejun Heo <htejun@gmail.com>
>>
>>---
>>
>>Jeff, first of all, thanks for the pointer.  I have two more
>>questions.
>>
>>* I make ATA_MAX_SECTORS_LBA48 65535 (the 0000h case is supposed to be
>>  broken, right?); however, the comment says 65534.  Should it be
>>  65534?
> 
> 
> Since we never noticed any breakage on !sectors on lba28, I think we can
> safely assume that !sectors will work fine for lba48 as well. So why not
> just make it full 64k, eg 65536? ->max_hw_sectors is an unsigned int
> now, so 64k wont overflow it.
> 

Hello, Jens.

libata currently sets max_sectors to 200 (ATA_MAX_SECTORS) on lba28. 
Are you talking about IDE driver?  IDE driver seems to set max_sectors 
to 256 on probe and make it 2048 while setting up ide disk if lba48.

Hmmm... Can we really trust all the firmwares?  I just feel that some 
drive out there ought have screwed up about nsect == 00h/0000h case.

Thanks.

-- 
tejun