Gary Thomas wrote:

Gary Thomas wrote:

quoted

I had a stable port of 2.6.26 for my 834x hardware, with a
frame buffer on a PCI device.  After I upgraded to 2.6.28,
this isn't working any more.  The frame buffer code is happily
writing to a mapped [memory] space on the PCI card, but nothing
is happening.

Did something [subtle] change in how the PCI is handled in
this timeframe?  Perhaps with how PCI devices are mapped or
enabled?  I've looked at the changes between the two versions,
but nothing leaps out at me.

n.b. I have other devices on the PCI bus, such as a SATA
controller, which work the same in both versions.

Thanks for any ideas

The difference seems to be in how the PCI bus gets mapped.

In the working, 2.6.26 based kernel, 'lspci -v' shows this:

00:00.0 Bridge: Unknown device 1957:0084 (rev 11)
        Flags: bus master, 66MHz, fast devsel, latency 0
        Memory at cc000000 (32-bit, non-prefetchable) [size=1M]
        Memory at c0000000 (64-bit, prefetchable) [size=128M]
        Memory at cc143100 (64-bit, non-prefetchable) [size=1]
        Capabilities: [48] #06 [0000]

00:0a.0 Network controller: Unknown device 001c:0001 (rev 02)
        Subsystem: Unknown device 001c:0004
        Flags: medium devsel, IRQ 22
        Memory at cc120000 (32-bit, non-prefetchable) [size=64K]
        Memory at cc130000 (32-bit, non-prefetchable) [size=64K]

00:0b.0 Mass storage controller: Promise Technology, Inc. PDC40775 (SATA 300 TX2plus) (rev 02)
        Subsystem: Promise Technology, Inc. Unknown device 3573
        Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 23
        I/O ports at 1000 [size=128]
        I/O ports at 1100 [size=256]
        Memory at cc140000 (32-bit, non-prefetchable) [size=4K]
        Memory at cc100000 (32-bit, non-prefetchable) [size=128K]
        Capabilities: [60] Power Management version 2

00:0c.0 Display controller: Fujitsu Limited. Unknown device 2019 (rev 01)
        Flags: bus master, medium devsel, latency 0, IRQ 24
        Memory at c8000000 (32-bit, non-prefetchable) [size=64M]

00:0d.0 USB Controller: Philips Semiconductors USB 1.1 Host Controller (rev 11) (prog-if 10 [OHCI])
        Subsystem: Philips Semiconductors USB 1.1 Host Controller
        Flags: bus master, medium devsel, latency 0, IRQ 25
        Memory at cc141000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [dc] Power Management version 2

00:0d.1 USB Controller: Philips Semiconductors USB 1.1 Host Controller (rev 11) (prog-if 10 [OHCI])
        Subsystem: Philips Semiconductors USB 1.1 Host Controller
        Flags: bus master, medium devsel, latency 0, IRQ 25
        Memory at cc142000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [dc] Power Management version 2

00:0d.2 USB Controller: Philips Semiconductors USB 2.0 Host Controller (rev 11) (prog-if 20 [EHCI])
        Subsystem: Philips Semiconductors USB 2.0 Host Controller
        Flags: bus master, medium devsel, latency 0, IRQ 25
        Memory at cc143000 (32-bit, non-prefetchable) [size=256]
        Capabilities: [dc] Power Management version 2

This is what 2.6.28 shows:

00:00.0 Bridge: Unknown device 1957:0084 (rev 11)
        Flags: bus master, 66MHz, fast devsel, latency 0
        Memory at <unassigned> (64-bit, prefetchable)
        Memory at <unassigned> (64-bit, non-prefetchable)
        Capabilities: [48] #06 [0000]

00:0a.0 Network controller: Unknown device 001c:0001 (rev 02)
        Subsystem: Unknown device 001c:0004
        Flags: medium devsel, IRQ 16
        Memory at c4020000 (32-bit, non-prefetchable) [size=64K]
        Memory at c4030000 (32-bit, non-prefetchable) [size=64K]

00:0b.0 Mass storage controller: Promise Technology, Inc. PDC40775 (SATA 300 TX2plus) (rev 02)
        Subsystem: Promise Technology, Inc. Unknown device 3573
        Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 21
        I/O ports at 1000 [size=128]
        I/O ports at 1100 [size=256]
        Memory at c4040000 (32-bit, non-prefetchable) [size=4K]
        Memory at c4000000 (32-bit, non-prefetchable) [size=128K]
        Capabilities: [60] Power Management version 2

00:0c.0 Display controller: Fujitsu Limited. Unknown device 2019 (rev 01)
        Flags: bus master, medium devsel, latency 0, IRQ 22
        [virtual] Memory at c0000000 (32-bit, non-prefetchable) [size=64M]

00:0d.0 USB Controller: Philips Semiconductors USB 1.1 Host Controller (rev 11) (prog-if 10 [OHCI])
        Subsystem: Philips Semiconductors USB 1.1 Host Controller
        Flags: bus master, medium devsel, latency 0, IRQ 23
        Memory at c4041000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [dc] Power Management version 2

00:0d.1 USB Controller: Philips Semiconductors USB 1.1 Host Controller (rev 11) (prog-if 10 [OHCI])
        Subsystem: Philips Semiconductors USB 1.1 Host Controller
        Flags: bus master, medium devsel, latency 0, IRQ 23
        Memory at c4042000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [dc] Power Management version 2

00:0d.2 USB Controller: Philips Semiconductors USB 2.0 Host Controller (rev 11) (prog-if 20 [EHCI])
        Subsystem: Philips Semiconductors USB 2.0 Host Controller
        Flags: bus master, medium devsel, latency 0, IRQ 23
        Memory at c4043000 (32-bit, non-prefetchable) [size=256]
        Capabilities: [dc] Power Management version 2

The [two] big differences I see are that the video card (00:0d.0)
is being assigned 0xC0000000, which lspci marks as "virtual".
I think I've had trouble in the past with memory regions which
started at 0 relative to the PCI space.  Also "virtual" concerns me.

Does this spark any ideas from anyone?

n.b. "virtual" means that Linux reports that the device has
been mapped to 0xC0000000, but the device address register
is still unset :-(  How can this happen?


-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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