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* NEC ND-4550A problems reading DVD-R
@ 2011-02-28 21:36 Krzysztof Halasa
  2011-03-01  8:01 ` Tejun Heo
  0 siblings, 1 reply; 8+ messages in thread
From: Krzysztof Halasa @ 2011-02-28 21:36 UTC (permalink / raw)
  To: linux-ide, lkml, Tejun Heo

Hi,

Google suggests it may be a common problem with NEC ND-4550A DVD-RW
drives.

First thing: the drive frequently needs a lot of time to recognize the
disc, sometimes more than the usual 30 seconds SCSI timeout. I tried to
"echo 100 > /sys/block/sr0/device/timeout" but it doesn't seem to change
anything, should it? The timeout still occurs after 30 seconds (I'm not
pushing the disc tray manually, the mount pulls it in for me).

ata7.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
sr 6:0:0:0: CDB: Start/Stop Unit: 1b 00 00 00 03 00
ata7.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0
         res 40/00:02:00:08:00/00:00:00:00:00/a0 Emask 0x4 (timeout)
ata7.00: status: { DRDY }
ata7: link is slow to respond, please be patient (ready=0)
ata7: device not ready (errno=-16), forcing hardreset
ata7: soft resetting link
ata7.00: FORCE: xfer_mask set to udma33
ata7.00: configured for UDMA/33
ata7: EH complete
sr0: CDROM (ioctl) error, command: Start/Stop Unit 1b 00 00 00 03 00
sr: Sense Key : Aborted Command [current] [descriptor]
sr: Add. Sense: No additional sense information

I'm using the "FORCE" to prevent Linux from downgrading to PIO modes,
they are a performance disaster.

Is there any other way to have a longer command timeout (perhaps while
loading the disc only)?


Second thing: the drive frequently responds to READ_CAPACITY with a zero
(one sector).

sr_cd_check() - for both working and non-working cases:
...
        case VENDOR_SCSI3:
                cgc.cmd[0] = READ_TOC;
                cgc.cmd[8] = 12;
                cgc.cmd[9] = 0x40;
                cgc.buffer = buffer;
                cgc.buflen = 12;
                cgc.quiet = 1;
                cgc.data_direction = DMA_FROM_DEVICE;
                cgc.timeout = VENDOR_TIMEOUT;
                rc = sr_do_ioctl(cd, &cgc);

At this point rc = 0, buffer = 00 0A 01 01 00 14 01 00 00 00 00 00.

Then get_sectorsize() does READ_CAPACITY which completes without errors.
Sometimes the scsi_execute_req() returns e.g.:

	buffer = 00 23 01 6F 00 00 08 00

which results in set_capacity(9176512)
and sometimes the return value is:

	buffer = 00 00 00 00 00 00 08 00

which sets the media size to 2048 bytes (cat /sys/block/sr0/size returns
4, the kernel "attempts to access beyond end of device" etc).

I'm aware of http://bugzilla.kernel.org/show_bug.cgi?id=9668 and that
the fix for it is in the tree, but it doesn't really fix this issue for
me.

The following work-around makes the disc readable:

	if (!cdrom_get_last_written(&cd->cdi, &last_written))
		cd->capacity = max_t(long, cd->capacity, last_written);

+	if (cd->capacity == 1)
+		cd->capacity = 50 /* GiB */ * 1024 * 1024 / 2;
+
	sector_size = (buffer[4] << 24) |
		(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];

Though I'm sure there is much better way to fix it.

When the drive can't read the medium size, dvd+rw-mediainfo prints:

INQUIRY:                [_NEC    ][DVD_RW ND-4550A ][1.09]
GET [CURRENT] CONFIGURATION:
 Mounted Media:         14h, DVD-RW Sequential
 Media ID:              MCC 03RG20
 Current Write Speed:   6.1x1385=8467KB/s
 Write Speed #0:        6.1x1385=8467KB/s
 Write Speed #1:        5.1x1385=7056KB/s
 Write Speed #2:        4.1x1385=5645KB/s
 Write Speed #3:        3.1x1385=4234KB/s
 Write Speed #4:        2.0x1385=2822KB/s
 Write Speed #5:        1.0x1385=1411KB/s
GET [CURRENT] PERFORMANCE:
 Write Performance:     1.0x1385=1385KB/s@[0 -> 2297888]
:-( empty GET PERFORMACE descriptor
READ DVD STRUCTURE[#10h]:
 Media Book Type:       00h, DVD-ROM book [revision 0]
 Legacy lead-out at:    2298496*2KB=4707319808
READ DVD STRUCTURE[#0h]:
 Media Book Type:       25h, DVD-R book [revision 5]
 Last border-out at:    2045*2KB=4188160
READ DISC INFORMATION:
 Disc status:           complete
 Number of Sessions:    1
 State of Last Session: complete
 Number of Tracks:      1
READ FORMAT CAPACITIES:
 formatted:             0*2048=0
 00h(800):              2297888*2048=4706074624
 10h(10):               2297888*2048=4706074624
 15h(10):               2297888*2048=4706074624
READ TRACK INFORMATION[#1]:
 Track State:           complete,damaged
 Track Start Address:   0*2KB
 Free Blocks:           0*2KB
 Track Size:            1*2KB
FABRICATED TOC:
 Track#1  :             14@0
 Track#AA :             14@2297888
 Multi-session Info:    #1@0
READ CAPACITY:          0*2048=0

When the medium size is detected the output differs (the same disc, it
works and doesn't work randomly):
- Mounted Media:         14h, DVD-RW Sequential
+ Mounted Media:         11h, DVD-R Sequential
- Write Performance:     1.0x1385=1385KB/s@[0 -> 2297888]
-:-( empty GET PERFORMACE descriptor
+ Write Performance:     6.6x1385=9141KB/s@0 -> 16.0x1385=22160KB/s@2294128
+ Speed Descriptor#0:    03/2294128 R@16.0x1385=22160KB/s W@16.0x1385=22160KB/s
+ Speed Descriptor#1:    03/2294128 R@12.0x1385=16620KB/s W@12.0x1385=16620KB/s
+ Speed Descriptor#2:    00/2294128 R@8.0x1385=11080KB/s W@8.0x1385=11080KB/s
+ Speed Descriptor#3:    00/2294128 R@8.0x1385=11080KB/s W@6.0x1385=8310KB/s
+ Speed Descriptor#4:    00/2294128 R@5.0x1385=6925KB/s W@4.0x1385=5540KB/s
+ Speed Descriptor#5:    00/2294128 R@5.0x1385=6925KB/s W@2.0x1385=2770KB/s
-READ FORMAT CAPACITIES:
- formatted:             0*2048=0
- 00h(800):              2297888*2048=4706074624
- 10h(10):               2297888*2048=4706074624
- 15h(10):               2297888*2048=4706074624
 READ TRACK INFORMATION[#1]:
- Track State:           complete,damaged
+ Track State:           complete incremental
  Track Start Address:   0*2KB
  Free Blocks:           0*2KB
- Track Size:            1*2KB
+ Track Size:            2294128*2KB
+ Last Recorded Address: 2294127*2KB
 FABRICATED TOC:
  Track#1  :             14@0
- Track#AA :             14@2297888
+ Track#AA :             14@2294128
  Multi-session Info:    #1@0
-READ CAPACITY:          0*2048=0
+READ CAPACITY:          2294128*2048=4698374144


Any ideas?

Linux v2.6.37.2, x86-64 SMP, the discs are Verbatim DVD-R single layer.
With the "50 GiB" patch applied and without triggering the SCSI timeout
(after the disc is inserted - i.e. inserting by hand and waiting for the
drive to recognize the disc before trying to mount it) the discs are
perfectly readable. Also, a different drive (such as old DVD-ROM/CD-RW
Toshiba "combo") reads them without problems.

This is a PATA drive connected to JMicron JMB363 PATA port.
-- 
Krzysztof Halasa

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: NEC ND-4550A problems reading DVD-R
  2011-02-28 21:36 NEC ND-4550A problems reading DVD-R Krzysztof Halasa
@ 2011-03-01  8:01 ` Tejun Heo
  2011-03-01 10:01   ` Krzysztof Halasa
  2011-03-01 13:48   ` Mark Lord
  0 siblings, 2 replies; 8+ messages in thread
From: Tejun Heo @ 2011-03-01  8:01 UTC (permalink / raw)
  To: Krzysztof Halasa; +Cc: linux-ide, lkml, linux-scsi

(cc'ing linux-scsi and quoting whole body)

Hello,

On Mon, Feb 28, 2011 at 10:36:27PM +0100, Krzysztof Halasa wrote:
> ata7.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
> sr 6:0:0:0: CDB: Start/Stop Unit: 1b 00 00 00 03 00
> ata7.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0
>          res 40/00:02:00:08:00/00:00:00:00:00/a0 Emask 0x4 (timeout)
> ata7.00: status: { DRDY }
> ata7: link is slow to respond, please be patient (ready=0)
> ata7: device not ready (errno=-16), forcing hardreset
> ata7: soft resetting link
> ata7.00: FORCE: xfer_mask set to udma33
> ata7.00: configured for UDMA/33
> ata7: EH complete
> sr0: CDROM (ioctl) error, command: Start/Stop Unit 1b 00 00 00 03 00
> sr: Sense Key : Aborted Command [current] [descriptor]
> sr: Add. Sense: No additional sense information
> 
> I'm using the "FORCE" to prevent Linux from downgrading to PIO modes,
> they are a performance disaster.
> 
> Is there any other way to have a longer command timeout (perhaps while
> loading the disc only)?

I think that's determined by drivers/scsi/sr.h::SR_TIMEOUT which is
hardcoded to be 30 seconds.  Maybe it's better to move it to use the
block parameter.  Anyways, the drive actually takes longer than 30secs
to recognize the media?

> Second thing: the drive frequently responds to READ_CAPACITY with a zero
> (one sector).
> 
> sr_cd_check() - for both working and non-working cases:
> ...
>         case VENDOR_SCSI3:
>                 cgc.cmd[0] = READ_TOC;
>                 cgc.cmd[8] = 12;
>                 cgc.cmd[9] = 0x40;
>                 cgc.buffer = buffer;
>                 cgc.buflen = 12;
>                 cgc.quiet = 1;
>                 cgc.data_direction = DMA_FROM_DEVICE;
>                 cgc.timeout = VENDOR_TIMEOUT;
>                 rc = sr_do_ioctl(cd, &cgc);
> 
> At this point rc = 0, buffer = 00 0A 01 01 00 14 01 00 00 00 00 00.
> 
> Then get_sectorsize() does READ_CAPACITY which completes without errors.
> Sometimes the scsi_execute_req() returns e.g.:
> 
> 	buffer = 00 23 01 6F 00 00 08 00
> 
> which results in set_capacity(9176512)
> and sometimes the return value is:
> 
> 	buffer = 00 00 00 00 00 00 08 00
> 
> which sets the media size to 2048 bytes (cat /sys/block/sr0/size returns
> 4, the kernel "attempts to access beyond end of device" etc).
> 
> I'm aware of http://bugzilla.kernel.org/show_bug.cgi?id=9668 and that
> the fix for it is in the tree, but it doesn't really fix this issue for
> me.
> 
> The following work-around makes the disc readable:
> 
> 	if (!cdrom_get_last_written(&cd->cdi, &last_written))
> 		cd->capacity = max_t(long, cd->capacity, last_written);
> 
> +	if (cd->capacity == 1)
> +		cd->capacity = 50 /* GiB */ * 1024 * 1024 / 2;
> +
> 	sector_size = (buffer[4] << 24) |
> 		(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
> 
> Though I'm sure there is much better way to fix it.

Eeek, ugly.  Isn't there firmware update available for the drive?

> When the drive can't read the medium size, dvd+rw-mediainfo prints:
> 
> INQUIRY:                [_NEC    ][DVD_RW ND-4550A ][1.09]
> GET [CURRENT] CONFIGURATION:
>  Mounted Media:         14h, DVD-RW Sequential
>  Media ID:              MCC 03RG20
>  Current Write Speed:   6.1x1385=8467KB/s
>  Write Speed #0:        6.1x1385=8467KB/s
>  Write Speed #1:        5.1x1385=7056KB/s
>  Write Speed #2:        4.1x1385=5645KB/s
>  Write Speed #3:        3.1x1385=4234KB/s
>  Write Speed #4:        2.0x1385=2822KB/s
>  Write Speed #5:        1.0x1385=1411KB/s
> GET [CURRENT] PERFORMANCE:
>  Write Performance:     1.0x1385=1385KB/s@[0 -> 2297888]
> :-( empty GET PERFORMACE descriptor
> READ DVD STRUCTURE[#10h]:
>  Media Book Type:       00h, DVD-ROM book [revision 0]
>  Legacy lead-out at:    2298496*2KB=4707319808
> READ DVD STRUCTURE[#0h]:
>  Media Book Type:       25h, DVD-R book [revision 5]
>  Last border-out at:    2045*2KB=4188160
> READ DISC INFORMATION:
>  Disc status:           complete
>  Number of Sessions:    1
>  State of Last Session: complete
>  Number of Tracks:      1
> READ FORMAT CAPACITIES:
>  formatted:             0*2048=0
>  00h(800):              2297888*2048=4706074624
>  10h(10):               2297888*2048=4706074624
>  15h(10):               2297888*2048=4706074624
> READ TRACK INFORMATION[#1]:
>  Track State:           complete,damaged
>  Track Start Address:   0*2KB
>  Free Blocks:           0*2KB
>  Track Size:            1*2KB
> FABRICATED TOC:
>  Track#1  :             14@0
>  Track#AA :             14@2297888
>  Multi-session Info:    #1@0
> READ CAPACITY:          0*2048=0
> 
> When the medium size is detected the output differs (the same disc, it
> works and doesn't work randomly):
> - Mounted Media:         14h, DVD-RW Sequential
> + Mounted Media:         11h, DVD-R Sequential
> - Write Performance:     1.0x1385=1385KB/s@[0 -> 2297888]
> -:-( empty GET PERFORMACE descriptor
> + Write Performance:     6.6x1385=9141KB/s@0 -> 16.0x1385=22160KB/s@2294128
> + Speed Descriptor#0:    03/2294128 R@16.0x1385=22160KB/s W@16.0x1385=22160KB/s
> + Speed Descriptor#1:    03/2294128 R@12.0x1385=16620KB/s W@12.0x1385=16620KB/s
> + Speed Descriptor#2:    00/2294128 R@8.0x1385=11080KB/s W@8.0x1385=11080KB/s
> + Speed Descriptor#3:    00/2294128 R@8.0x1385=11080KB/s W@6.0x1385=8310KB/s
> + Speed Descriptor#4:    00/2294128 R@5.0x1385=6925KB/s W@4.0x1385=5540KB/s
> + Speed Descriptor#5:    00/2294128 R@5.0x1385=6925KB/s W@2.0x1385=2770KB/s
> -READ FORMAT CAPACITIES:
> - formatted:             0*2048=0
> - 00h(800):              2297888*2048=4706074624
> - 10h(10):               2297888*2048=4706074624
> - 15h(10):               2297888*2048=4706074624
>  READ TRACK INFORMATION[#1]:
> - Track State:           complete,damaged
> + Track State:           complete incremental
>   Track Start Address:   0*2KB
>   Free Blocks:           0*2KB
> - Track Size:            1*2KB
> + Track Size:            2294128*2KB
> + Last Recorded Address: 2294127*2KB
>  FABRICATED TOC:
>   Track#1  :             14@0
> - Track#AA :             14@2297888
> + Track#AA :             14@2294128
>   Multi-session Info:    #1@0
> -READ CAPACITY:          0*2048=0
> +READ CAPACITY:          2294128*2048=4698374144
> 
> 
> Any ideas?
> 
> Linux v2.6.37.2, x86-64 SMP, the discs are Verbatim DVD-R single layer.
> With the "50 GiB" patch applied and without triggering the SCSI timeout
> (after the disc is inserted - i.e. inserting by hand and waiting for the
> drive to recognize the disc before trying to mount it) the discs are
> perfectly readable. Also, a different drive (such as old DVD-ROM/CD-RW
> Toshiba "combo") reads them without problems.
> 
> This is a PATA drive connected to JMicron JMB363 PATA port.
> -- 
> Krzysztof Halasa
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ide" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
tejun

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: NEC ND-4550A problems reading DVD-R
  2011-03-01  8:01 ` Tejun Heo
@ 2011-03-01 10:01   ` Krzysztof Halasa
  2011-03-01 13:48   ` Mark Lord
  1 sibling, 0 replies; 8+ messages in thread
From: Krzysztof Halasa @ 2011-03-01 10:01 UTC (permalink / raw)
  To: Tejun Heo; +Cc: linux-ide, lkml, linux-scsi

Tejun Heo <tj@kernel.org> writes:

> I think that's determined by drivers/scsi/sr.h::SR_TIMEOUT which is
> hardcoded to be 30 seconds.  Maybe it's better to move it to use the
> block parameter.  Anyways, the drive actually takes longer than 30secs
> to recognize the media?

Yes, sometimes it takes e.g. 18 seconds, and sometimes it's 33 secs or
something alike. It's quite random.

Perhaps we should have a longer timeout only while mounting the media?

> Eeek, ugly.  Isn't there firmware update available for the drive?

1.09 is already the latest. It's a '2005 drive.

Thanks.
-- 
Krzysztof Halasa

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: NEC ND-4550A problems reading DVD-R
  2011-03-01  8:01 ` Tejun Heo
  2011-03-01 10:01   ` Krzysztof Halasa
@ 2011-03-01 13:48   ` Mark Lord
  2011-03-01 15:47     ` Stephen Clark
  1 sibling, 1 reply; 8+ messages in thread
From: Mark Lord @ 2011-03-01 13:48 UTC (permalink / raw)
  To: Tejun Heo; +Cc: Krzysztof Halasa, linux-ide, lkml, linux-scsi

On 11-03-01 03:01 AM, Tejun Heo wrote:
..
> I think that's determined by drivers/scsi/sr.h::SR_TIMEOUT which is
> hardcoded to be 30 seconds.  Maybe it's better to move it to use the
> block parameter.  Anyways, the drive actually takes longer than 30secs
> to recognize the media?

That slow behaviour is not uncommon, especially as drives struggle
to recognize various forms of copy-protected media (DVD-Video).
A longer default, or tuneable timeout, would help.

Cheers


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: NEC ND-4550A problems reading DVD-R
  2011-03-01 13:48   ` Mark Lord
@ 2011-03-01 15:47     ` Stephen Clark
  2011-03-04 11:07       ` Tejun Heo
  0 siblings, 1 reply; 8+ messages in thread
From: Stephen Clark @ 2011-03-01 15:47 UTC (permalink / raw)
  To: Mark Lord; +Cc: Tejun Heo, Krzysztof Halasa, linux-ide, lkml, linux-scsi

On 03/01/2011 08:48 AM, Mark Lord wrote:
> On 11-03-01 03:01 AM, Tejun Heo wrote:
> ..
>    
>> I think that's determined by drivers/scsi/sr.h::SR_TIMEOUT which is
>> hardcoded to be 30 seconds.  Maybe it's better to move it to use the
>> block parameter.  Anyways, the drive actually takes longer than 30secs
>> to recognize the media?
>>      
> That slow behaviour is not uncommon, especially as drives struggle
> to recognize various forms of copy-protected media (DVD-Video).
> A longer default, or tuneable timeout, would help.
>
> Cheers
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>
>    
I agree with Mark, this should be a user tuneable value. My 2006 LG 
dvd-rw frequently times out
trying to identify the media. But after numerous timeout error messages 
it usually suceeds.

-- 

"They that give up essential liberty to obtain temporary safety,
deserve neither liberty nor safety."  (Ben Franklin)

"The course of history shows that as a government grows, liberty
decreases."  (Thomas Jefferson)




^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: NEC ND-4550A problems reading DVD-R
  2011-03-01 15:47     ` Stephen Clark
@ 2011-03-04 11:07       ` Tejun Heo
  2011-03-04 14:09         ` Stephen Clark
  2011-03-04 22:16         ` Jens Axboe
  0 siblings, 2 replies; 8+ messages in thread
From: Tejun Heo @ 2011-03-04 11:07 UTC (permalink / raw)
  To: Stephen Clark
  Cc: Mark Lord, Krzysztof Halasa, linux-ide, lkml, linux-scsi,
	Jens Axboe, James Bottomley

(cc'ing Jens and James)

On Tue, Mar 01, 2011 at 10:47:41AM -0500, Stephen Clark wrote:
> On 03/01/2011 08:48 AM, Mark Lord wrote:
> >On 11-03-01 03:01 AM, Tejun Heo wrote:
> >..
> >>I think that's determined by drivers/scsi/sr.h::SR_TIMEOUT which is
> >>hardcoded to be 30 seconds.  Maybe it's better to move it to use the
> >>block parameter.  Anyways, the drive actually takes longer than 30secs
> >>to recognize the media?
> >That slow behaviour is not uncommon, especially as drives struggle
> >to recognize various forms of copy-protected media (DVD-Video).
> >A longer default, or tuneable timeout, would help.
>
> I agree with Mark, this should be a user tuneable value. My 2006 LG
> dvd-rw frequently times out
> trying to identify the media. But after numerous timeout error
> messages it usually suceeds.

I don't think it should be a user tunable value.  It should be
something automatic.  I mean, how many would know to go some cryptic
place and increase sr probing timeout?

At the same time, increasing it for other cases is quite unattractive,
so it probably would be a good idea to only use higher timeout value
for the TUR right after media presence change event.

Anyone interested in doing it?

Thanks.

-- 
tejun

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: NEC ND-4550A problems reading DVD-R
  2011-03-04 11:07       ` Tejun Heo
@ 2011-03-04 14:09         ` Stephen Clark
  2011-03-04 22:16         ` Jens Axboe
  1 sibling, 0 replies; 8+ messages in thread
From: Stephen Clark @ 2011-03-04 14:09 UTC (permalink / raw)
  To: Tejun Heo
  Cc: Mark Lord, Krzysztof Halasa, linux-ide, lkml, linux-scsi,
	Jens Axboe, James Bottomley

On 03/04/2011 06:07 AM, Tejun Heo wrote:
> (cc'ing Jens and James)
>
> On Tue, Mar 01, 2011 at 10:47:41AM -0500, Stephen Clark wrote:
>    
>> On 03/01/2011 08:48 AM, Mark Lord wrote:
>>      
>>> On 11-03-01 03:01 AM, Tejun Heo wrote:
>>> ..
>>>        
>>>> I think that's determined by drivers/scsi/sr.h::SR_TIMEOUT which is
>>>> hardcoded to be 30 seconds.  Maybe it's better to move it to use the
>>>> block parameter.  Anyways, the drive actually takes longer than 30secs
>>>> to recognize the media?
>>>>          
>>> That slow behaviour is not uncommon, especially as drives struggle
>>> to recognize various forms of copy-protected media (DVD-Video).
>>> A longer default, or tuneable timeout, would help.
>>>        
>> I agree with Mark, this should be a user tuneable value. My 2006 LG
>> dvd-rw frequently times out
>> trying to identify the media. But after numerous timeout error
>> messages it usually suceeds.
>>      
> I don't think it should be a user tunable value.  It should be
> something automatic.  I mean, how many would know to go some cryptic
> place and increase sr probing timeout?
>
> At the same time, increasing it for other cases is quite unattractive,
> so it probably would be a good idea to only use higher timeout value
> for the TUR right after media presence change event.
>
> Anyone interested in doing it?
>
> Thanks.
>
>    
I don't see this as being any different than all the other obfuscated 
tunable values that already
exists. At least I could google or look around for a tunable and maybe 
change it myself instead of having to
patch the source.

-- 

"They that give up essential liberty to obtain temporary safety,
deserve neither liberty nor safety."  (Ben Franklin)

"The course of history shows that as a government grows, liberty
decreases."  (Thomas Jefferson)




^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: NEC ND-4550A problems reading DVD-R
  2011-03-04 11:07       ` Tejun Heo
  2011-03-04 14:09         ` Stephen Clark
@ 2011-03-04 22:16         ` Jens Axboe
  1 sibling, 0 replies; 8+ messages in thread
From: Jens Axboe @ 2011-03-04 22:16 UTC (permalink / raw)
  To: Tejun Heo
  Cc: Stephen Clark, Mark Lord, Krzysztof Halasa, linux-ide, lkml,
	linux-scsi, James Bottomley

On 2011-03-04 12:07, Tejun Heo wrote:
> (cc'ing Jens and James)
> 
> On Tue, Mar 01, 2011 at 10:47:41AM -0500, Stephen Clark wrote:
>> On 03/01/2011 08:48 AM, Mark Lord wrote:
>>> On 11-03-01 03:01 AM, Tejun Heo wrote:
>>> ..
>>>> I think that's determined by drivers/scsi/sr.h::SR_TIMEOUT which is
>>>> hardcoded to be 30 seconds.  Maybe it's better to move it to use the
>>>> block parameter.  Anyways, the drive actually takes longer than 30secs
>>>> to recognize the media?
>>> That slow behaviour is not uncommon, especially as drives struggle
>>> to recognize various forms of copy-protected media (DVD-Video).
>>> A longer default, or tuneable timeout, would help.
>>
>> I agree with Mark, this should be a user tuneable value. My 2006 LG
>> dvd-rw frequently times out
>> trying to identify the media. But after numerous timeout error
>> messages it usually suceeds.
> 
> I don't think it should be a user tunable value.  It should be
> something automatic.  I mean, how many would know to go some cryptic
> place and increase sr probing timeout?
> 
> At the same time, increasing it for other cases is quite unattractive,
> so it probably would be a good idea to only use higher timeout value
> for the TUR right after media presence change event.
> 
> Anyone interested in doing it?

A higher timeout would be the easy fix. And unless there's a solid way
to detect whether the drive is truly hung or just busy trying to grok
the media, I think it's the only feasible solution.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2011-03-04 22:16 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-02-28 21:36 NEC ND-4550A problems reading DVD-R Krzysztof Halasa
2011-03-01  8:01 ` Tejun Heo
2011-03-01 10:01   ` Krzysztof Halasa
2011-03-01 13:48   ` Mark Lord
2011-03-01 15:47     ` Stephen Clark
2011-03-04 11:07       ` Tejun Heo
2011-03-04 14:09         ` Stephen Clark
2011-03-04 22:16         ` Jens Axboe

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