Fri, 28 Oct 2016 14:48:47 +1100 (AEDT) On Thu, 27 Oct 2016, Michael Schmitz wrote:
> Am 03.08.2016 um 16:16 schrieb Finn Thain: > > > > On Tue, 2 Aug 2016, Mac User wrote: > > > > > > Please send pictures. You can use the kernel parameter > > > > "fbcon=font:ProFont6x11" to get more text on the screen if it > > > > scrolls too fast. > > > > > > > > > > Please see attached. Thanks.. > > > [...] > > > scsi host0: esp > > > scsi 0:0:0:0: Direct-Access SEAGATE ST318417N 0105 PQ: 0 ANSI: 3 > > > scsi target0:0:0: Beginning Domain Validation > > > scsi host0: Reconnect IRQ2 timeout > > > > A bit of Googling tells me that I've been here before (I had forgotten): > > > > commit 02507a80b35edd720480540d917e9f92cc371009 > > Author: Finn Thain <fth...@telegraphics.com.au> > > Date: Sat Dec 5 12:30:42 2009 +1100 > > > > [SCSI] mac_esp: fix PIO mode, take 2 > > > > The mac_esp PIO algorithm no longer works in 2.6.31 and crashes my > > Centris 660av. So here's a better one. > > > > Also, force async with esp_set_offset() rather than > > esp_slave_configure(). > > > > One of the SCSI drives I tested still doesn't like the PIO mode > > and fails with "esp: esp0: Reconnect IRQ2 timeout" (the same drive > > works fine in PDMA mode). > > > > This failure happens when esp_reconnect_with_tag() tries to read > > in two tag bytes but the chip only provides one (0x20). I don't > > know what causes this. I decided not to waste any more time trying > > to fix it because the best solution is to rip out the PIO mode > > altogether and use the DMA engine. > > > > > > So it appears that this bug is not a regression. I guess you have 3 > > options: find a compatible drive, implement DMA with the PSC chip, or > > debug the esp_reconnect_with_tag() implementation for PIO use. > > > > Apple never provided public documentation for the PSC chip, which is > > why there's no DMA support for SCSI on AV Quadras, and also why we > > have code like this in macmace.c: > > > > /* Not sure what this does */ > > > > while ((baka = psc_read_long(PSC_MYSTERY)) != > > psc_read_long(PSC_MYSTERY)); > > if (!(baka & 0x60000000)) return IRQ_NONE; > > > > You could tackle the esp_reconnect_with_tag() bug by increasing the > > ESP_RESELECT_TAG_LIMIT timeout and setting some kernel parameters: > > scsi_mod.scan=sync esp_scsi.esp_debug=0x241 > > > > In my experience, the only practical way to debug mac scsi drivers is > > to make the driver modular, boot over ethernet and then use insmod and > > rmmod to test changes to the module. > > > > > Hi Finn, > > the problem with trying to read two tag bytes does sound familiar - I > believe we ran into that one (or a similar one) while trying to revive > the Amiga ESP drivers. > That's intriguing. I hadn't realised that those zorro_esp discussions on the mailing lists (linked below) covered the same bug I saw in mac_esp in 2009. http://linux-m68k.vger.kernel.narkive.com/pMVlraRz/patch-0-2-experimental-amiga-zorro-esp-driver http://markmail.org/message/whgfl2d5jhk3y75t http://markmail.org/message/qxrwcdpc625mczml > Tuomas used scsi_deactivate_tcq() in a driver specific > esp_slave_configure() hook but that interface later disappeared. In the > last version I tested, I added the following code after domain > validation in the driver specific esp_slave_configure() > > + /* > + * Hardwire TQC capability of target _off_ after > + * domain validation (which might have probed and > + * negotiated TQC available) > + */ > + dev->tagged_supported = 0; > + dev->simple_tags = 0; > + > > I tried all sorts of things with the chip config registers, to no avail. Nonetheless this issue should probably be addressed in the core esp_scsi driver to avoid duplicating fixes in the board-specific code. If we can fix this issue in esp_scsi.c, it would be a good idea to get some reviews for a complete series of patches for the new zorro_esp.c as well as changes to esp_scsi.c and probably mac_esp.c too. > Your report that this only happens with some disks exonerates the driver The fact that zorro_esp is also affected gives me confidence in mac_esp. Maybe this is an erratum relating to the particular device found in the Quadra 660av, and has nothing to do with PIO/DMA/PDMA. Stan, can you check the markings on the SCSI chip in your 660av? It's most probably the largest device near the two SCSI connectors, possibly Am53C94? I wonder why this problem didn't affect the old ESP driver? (Stan pointed out earlier in this thread that "Debian 3.1 (with a Linux 2.2.25 kernel) works on the Quadra 660av".) -- > > HTH, > > Michael > >
