In 2.4.17-pre5, agp_generic_agp_enable() and serverworks_agp_enable()
were changed to look for AGP devices as coprocessors on non-VGA
devices as well as VGA devices.
But those functions contain TWO loops that scan for AGP devices (one
to collect the settings they support, and a second to update the
command registers), and 2.4.17-pre5 only changed the first loop in
each case. Shouldn't both loops be changed, as in the "agp_dev" patch
attached?
While looking at this code, I noticed a possible further improvement.
Currently it looks like this:
pci_for_each_dev(device)
{
if((((device->class >> 16) & 0xFF) != PCI_BASE_CLASS_DISPLAY) &&
(device->class != (PCI_CLASS_PROCESSOR_CO << 8)))
continue;
pci_read_config_dword(device, 0x04, &scratch);
if (!(scratch & 0x00100000))
continue;
pci_read_config_byte(device, 0x34, &cap_ptr);
if (cap_ptr != 0x00) {
do {
pci_read_config_dword(device,
cap_ptr, &cap_id);
if ((cap_id & 0xff) != 0x02)
cap_ptr = (cap_id >> 8) & 0xff;
}
while (((cap_id & 0xff) != 0x02) && (cap_ptr != 0x00));
}
if (cap_ptr != 0x00) {
...
The bulk of the above is just a reimplementation of pci_find_capability(),
so what about changing the whole shooting match to the following:
pci_for_each_dev(device) {
cap_ptr = pci_find_capability(device, PCI_CAP_ID_AGP);
if (cap_ptr != 0x00) {
...
Is there anything gained by checking the device class before looking
for the AGP capability? The "agp_find_cap" patch attached implements
this idea. I've compiled and booted kernels with both patches, but
they're otherwise untested.
-- Bjorn Helgaas - bjorn_helgaas@hp.com Linux Systems Operation R&D Hewlett-Packard --------------Boundary-00=_QCSEO4BKC9RU5RL7UM58 Content-Type: text/plain; charset="iso-8859-1"; name="agp_dev-2.4.18-pre6.patch" Content-Transfer-Encoding: 8bit Content-Disposition: attachment; filename="agp_dev-2.4.18-pre6.patch"diff -u -X /home/helgaas/exclude -r linux-2.4.18-pre6/drivers/char/agp/agpgart_be.c build/linux-2.4.18-pre6/drivers/char/agp/agpgart_be.c --- linux-2.4.18-pre6/drivers/char/agp/agpgart_be.c Wed Jan 23 10:16:39 2002 +++ build/linux-2.4.18-pre6/drivers/char/agp/agpgart_be.c Wed Jan 23 10:23:23 2002 @@ -506,8 +506,17 @@ * command registers. */ - while ((device = pci_find_class(PCI_CLASS_DISPLAY_VGA << 8, - device)) != NULL) { + pci_for_each_dev(device) + { + /* + * Enable AGP devices. Most will be VGA display but + * some may be coprocessors on non VGA devices too + */ + + if((((device->class >> 16) & 0xFF) != PCI_BASE_CLASS_DISPLAY) && + (device->class != (PCI_CLASS_PROCESSOR_CO << 8))) + continue; + pci_read_config_dword(device, 0x04, &scratch); if (!(scratch & 0x00100000)) @@ -3421,8 +3430,17 @@ * command registers. */ - while ((device = pci_find_class(PCI_CLASS_DISPLAY_VGA << 8, - device)) != NULL) { + pci_for_each_dev(device) + { + /* + * Enable AGP devices. Most will be VGA display but + * some may be coprocessors on non VGA devices too + */ + + if((((device->class >> 16) & 0xFF) != PCI_BASE_CLASS_DISPLAY) && + (device->class != (PCI_CLASS_PROCESSOR_CO << 8))) + continue; + pci_read_config_dword(device, 0x04, &scratch); if (!(scratch & 0x00100000))
--------------Boundary-00=_QCSEO4BKC9RU5RL7UM58 Content-Type: text/plain; charset="iso-8859-1"; name="agp_find_cap-2.4.18-pre6.patch" Content-Transfer-Encoding: 8bit Content-Disposition: attachment; filename="agp_find_cap-2.4.18-pre6.patch"
diff -u -X /home/helgaas/exclude -r linux-2.4.18-pre6/drivers/char/agp/agpgart_be.c build/linux-2.4.18-pre6-find_cap/drivers/char/agp/agpgart_be.c --- linux-2.4.18-pre6/drivers/char/agp/agpgart_be.c Wed Jan 23 10:16:39 2002 +++ build/linux-2.4.18-pre6-find_cap/drivers/char/agp/agpgart_be.c Wed Jan 23 10:32:12 2002 @@ -410,34 +410,8 @@ */ - pci_for_each_dev(device) - { - /* - * Enable AGP devices. Most will be VGA display but - * some may be coprocessors on non VGA devices too - */ - - if((((device->class >> 16) & 0xFF) != PCI_BASE_CLASS_DISPLAY) && - (device->class != (PCI_CLASS_PROCESSOR_CO << 8))) - continue; - - pci_read_config_dword(device, 0x04, &scratch); - - if (!(scratch & 0x00100000)) - continue; - - pci_read_config_byte(device, 0x34, &cap_ptr); - - if (cap_ptr != 0x00) { - do { - pci_read_config_dword(device, - cap_ptr, &cap_id); - - if ((cap_id & 0xff) != 0x02) - cap_ptr = (cap_id >> 8) & 0xff; - } - while (((cap_id & 0xff) != 0x02) && (cap_ptr != 0x00)); - } + pci_for_each_dev(device) { + cap_ptr = pci_find_capability(device, PCI_CAP_ID_AGP); if (cap_ptr != 0x00) { /* * Ok, here we have a AGP device. Disable impossible @@ -506,25 +480,8 @@ * command registers. */ - while ((device = pci_find_class(PCI_CLASS_DISPLAY_VGA << 8, - device)) != NULL) { - pci_read_config_dword(device, 0x04, &scratch); - - if (!(scratch & 0x00100000)) - continue; - - pci_read_config_byte(device, 0x34, &cap_ptr); - - if (cap_ptr != 0x00) { - do { - pci_read_config_dword(device, - cap_ptr, &cap_id); - - if ((cap_id & 0xff) != 0x02) - cap_ptr = (cap_id >> 8) & 0xff; - } - while (((cap_id & 0xff) != 0x02) && (cap_ptr != 0x00)); - } + pci_for_each_dev(device) { + cap_ptr = pci_find_capability(device, PCI_CAP_ID_AGP); if (cap_ptr != 0x00) pci_write_config_dword(device, cap_ptr + 8, command); } @@ -3326,24 +3283,8 @@ */ - pci_for_each_dev(device) - { - /* - * Enable AGP devices. Most will be VGA display but - * some may be coprocessors on non VGA devices too - */ - - if((((device->class >> 16) & 0xFF) != PCI_BASE_CLASS_DISPLAY) && - (device->class != (PCI_CLASS_PROCESSOR_CO << 8))) - continue; - - pci_read_config_dword(device, 0x04, &scratch); - - if (!(scratch & 0x00100000)) - continue; - - pci_read_config_byte(device, 0x34, &cap_ptr); - + pci_for_each_dev(device) { + cap_ptr = pci_find_capability(device, PCI_CAP_ID_AGP); if (cap_ptr != 0x00) { do { pci_read_config_dword(device, @@ -3421,25 +3362,8 @@ * command registers. */ - while ((device = pci_find_class(PCI_CLASS_DISPLAY_VGA << 8, - device)) != NULL) { - pci_read_config_dword(device, 0x04, &scratch); - - if (!(scratch & 0x00100000)) - continue; - - pci_read_config_byte(device, 0x34, &cap_ptr); - - if (cap_ptr != 0x00) { - do { - pci_read_config_dword(device, - cap_ptr, &cap_id); - - if ((cap_id & 0xff) != 0x02) - cap_ptr = (cap_id >> 8) & 0xff; - } - while (((cap_id & 0xff) != 0x02) && (cap_ptr != 0x00)); - } + pci_for_each_dev(device) { + cap_ptr = pci_find_capability(device, PCI_CAP_ID_AGP); if (cap_ptr != 0x00) pci_write_config_dword(device, cap_ptr + 8, command); } @@ -4037,20 +3961,7 @@ #endif /* CONFIG_AGP_SWORKS */ /* find capndx */ - pci_read_config_dword(dev, 0x04, &scratch); - if (!(scratch & 0x00100000)) - return -ENODEV; - - pci_read_config_byte(dev, 0x34, &cap_ptr); - if (cap_ptr != 0x00) { - do { - pci_read_config_dword(dev, cap_ptr, &cap_id); - - if ((cap_id & 0xff) != 0x02) - cap_ptr = (cap_id >> 8) & 0xff; - } - while (((cap_id & 0xff) != 0x02) && (cap_ptr != 0x00)); - } + cap_ptr = pci_find_capability(dev, PCI_CAP_ID_AGP); if (cap_ptr == 0x00) return -ENODEV; agp_bridge.capndx = cap_ptr;
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