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| author | Ryan Underwood <nemesis@icequake.net> | 2015-01-25 16:07:09 -0800 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-07-30 14:10:46 +0200 |
| commit | 9b534159031e187f14ab9ff78c01f114c0a79ce2 (patch) | |
| tree | c4837a9f12ca189601b40c11a6146180bc193384 | |
| parent | 9acf0767296ad6a71171c8405a972c7d6e6012c8 (diff) | |
| download | lwn-9b534159031e187f14ab9ff78c01f114c0a79ce2.tar.gz lwn-9b534159031e187f14ab9ff78c01f114c0a79ce2.zip | |
Disable write buffering on Toshiba ToPIC95
commit 2fb22a8042fe96b4220843f79241c116d90922c4 upstream.
Disable write buffering on the Toshiba ToPIC95 if it is enabled by
somebody (it is not supposed to be a power-on default according to
the datasheet). On the ToPIC95, practically no 32-bit Cardbus card
will work under heavy load without locking up the whole system if
this is left enabled. I tried about a dozen. It does not affect
16-bit cards. This is similar to the O2 bugs in early controller
revisions it seems.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=55961
Signed-off-by: Ryan C. Underwood <nemesis@icequake.net>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | drivers/pcmcia/topic.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/pcmcia/topic.h b/drivers/pcmcia/topic.h index 615a45a8fe86..582688fe7505 100644 --- a/drivers/pcmcia/topic.h +++ b/drivers/pcmcia/topic.h @@ -104,6 +104,9 @@ #define TOPIC_EXCA_IF_CONTROL 0x3e /* 8 bit */ #define TOPIC_EXCA_IFC_33V_ENA 0x01 +#define TOPIC_PCI_CFG_PPBCN 0x3e /* 16-bit */ +#define TOPIC_PCI_CFG_PPBCN_WBEN 0x0400 + static void topic97_zoom_video(struct pcmcia_socket *sock, int onoff) { struct yenta_socket *socket = container_of(sock, struct yenta_socket, socket); @@ -138,6 +141,7 @@ static int topic97_override(struct yenta_socket *socket) static int topic95_override(struct yenta_socket *socket) { u8 fctrl; + u16 ppbcn; /* enable 3.3V support for 16bit cards */ fctrl = exca_readb(socket, TOPIC_EXCA_IF_CONTROL); @@ -146,6 +150,18 @@ static int topic95_override(struct yenta_socket *socket) /* tell yenta to use exca registers to power 16bit cards */ socket->flags |= YENTA_16BIT_POWER_EXCA | YENTA_16BIT_POWER_DF; + /* Disable write buffers to prevent lockups under load with numerous + Cardbus cards, observed on Tecra 500CDT and reported elsewhere on the + net. This is not a power-on default according to the datasheet + but some BIOSes seem to set it. */ + if (pci_read_config_word(socket->dev, TOPIC_PCI_CFG_PPBCN, &ppbcn) == 0 + && socket->dev->revision <= 7 + && (ppbcn & TOPIC_PCI_CFG_PPBCN_WBEN)) { + ppbcn &= ~TOPIC_PCI_CFG_PPBCN_WBEN; + pci_write_config_word(socket->dev, TOPIC_PCI_CFG_PPBCN, ppbcn); + dev_info(&socket->dev->dev, "Disabled ToPIC95 Cardbus write buffers.\n"); + } + return 0; } |