Re: 2.4.20: possibly wrong handling of removeable scsi disks

[Andreas Steinmetz <ast@domdv.de>]

Willem Riede wrote:
> On 2003.02.23 07:17 Andreas Steinmetz wrote:
> 
>>             if( the_result != 0
>>                 && ((driver_byte(the_result) & DRIVER_SENSE) != 0)
>>===>            && SRpnt->sr_sense_buffer[2] == UNIT_ATTENTION
>>                 && SRpnt->sr_sense_buffer[12] == 0x3A ) {
>>                     rscsi_disks[i].capacity = 0x1fffff;
>>                     sector_size = 512;
>>                     rscsi_disks[i].device->changed = 1;
>>                     rscsi_disks[i].ready = 0;
>>    ...
>>
>>Now look at the marked (===>) lines above. I dont believe the test for 
>>UNIT_ATTENTION is correct. As far as I could find out the sense 
>>information from TEST_UNIT_READY should be either NO_SENSE, 
>>ILLEGAL_REQUEST or NOT_READY. As there is a check for 'medium not 
>>present' (0x3A) the test should be for NOT_READY instead of 
>>UNIT_ATTENTION. ger.kernel.org/majordomo-info.html
> 
> 
> You are right about this one. It should be NOT_READY, value 0x02.
> As a matter of fact, ASQ 0x3A is unique, so you could just delete the
> test of sr_sense_buffer[2] and it would work as expected.
> 

OK,
this still leaves the question why, if a device reports 'no medium 
found', the code still tries to do a READ_CAPACITY (multiple times). 
Capacity reporting depends on available medium, isn't possible when 
there's no medium found and causes unneeded communication and cpu 
overhead as well as syslog spamming.