diff options
Diffstat (limited to 'arch/x86/cpu/queensbay/tnc.c')
| -rw-r--r-- | arch/x86/cpu/queensbay/tnc.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/arch/x86/cpu/queensbay/tnc.c b/arch/x86/cpu/queensbay/tnc.c index 38082c4..b226e4c 100644 --- a/arch/x86/cpu/queensbay/tnc.c +++ b/arch/x86/cpu/queensbay/tnc.c @@ -6,6 +6,7 @@ #include <common.h> #include <dm.h> +#include <dm/device-internal.h> #include <pci.h> #include <asm/io.h> #include <asm/irq.h> @@ -53,6 +54,41 @@ static int __maybe_unused disable_igd(void) dm_pci_write_config32(igd, IGD_FD, FUNC_DISABLE); dm_pci_write_config32(sdvo, IGD_FD, FUNC_DISABLE); + /* + * After setting the function disable bit, IGD and SDVO devices will + * disappear in the PCI configuration space. This however creates an + * inconsistent state from a driver model PCI controller point of view, + * as these two PCI devices are still attached to its parent's child + * device list as maintained by the driver model. Some driver model PCI + * APIs like dm_pci_find_class(), are referring to the list to speed up + * the finding process instead of re-enumerating the whole PCI bus, so + * it gets the stale cached data which is wrong. + * + * Note x86 PCI enueration normally happens twice, in pre-relocation + * phase and post-relocation. One option might be to call disable_igd() + * in one of the pre-relocation initialization hooks so that it gets + * disabled in the first round, and when it comes to the second round + * driver model PCI will construct a correct list. Unfortunately this + * does not work as Intel FSP is used on this platform to perform low + * level initialization, and fsp_init_phase_pci() is called only once + * in the post-relocation phase. If we disable IGD and SDVO devices, + * fsp_init_phase_pci() simply hangs and never returns. + * + * So the only option we have is to manually remove these two devices. + */ + ret = device_remove(igd); + if (ret) + return ret; + ret = device_unbind(igd); + if (ret) + return ret; + ret = device_remove(sdvo); + if (ret) + return ret; + ret = device_unbind(sdvo); + if (ret) + return ret; + return 0; } |