Hello.
Kirill Smelkov wrote:
From: Dmitry Gryazin <gdu@xxxxxxxxxx>
We need to keep our kernel working on both legacy and modern hardware.
As it turned out, some boards don't have proper IDE DMA support for
CompactFlash (CF) adaptors, because pin connectors which relate to DMA are left
unsoldered (*).
To verify this we even bought external IDE CF adaptor which showed the same
symthoms, and then manually soldered pins that were left dangling, and voila,
DMA started to work!
Again, as they say, lots of manufacturers of not-so-new hardware did CF
soldering by the wrong way with respect to DMA, so we need a workaround.
For this __ide_dma_bad_drive function is enhance to check not only drives
blacklist but motherboards blacklist too.
Please apply before 2.6.29
(*) On IEI PCISA-C3/EDEN the kernel boots _very_ slowly, becuase we have lots
of DMA timer expiry:
<~30s pause>
hdc: dma_timer_epiry: dma_status == 0x21
hdc: DMA timeout error
...
hdc: DMA disabled
ide1: dma reset
<and the whole story repeats:>
<~30s pause>
hdc: dma_timer_epiry: dma_status == 0x21
...
Are you aware of ide_core.nodma= option which allows disabling DMA per
interface/drive? Read Documentation/ide/ide.txt please. I should note that
nodma option has been there for ages in one or other form.
Also see this posts from 2006 where they say this is usually a problem with CF
adapter not fully soldered:
http://lkml.org/lkml/2006/5/23/198
http://lkml.org/lkml/2006/6/20/164
Signed-off-by: Dmitry Gryazin <gdu@xxxxxxxxxx>
Signed-off-by: Kirill Smelkov <kirr@xxxxxxxxxx>
NAK.
diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index fffd117..adb5d9d 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -33,6 +33,21 @@
#include <linux/ide.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
+#include <linux/dmi.h>
+
+/* Internal structure for blacklisted boards */
+struct board_blacklist_entry {
+ const char *board_vendor;
+ const char *board_name;
+ const char *drive_name;
+};
+
+/* Blacklisted boards which have problems with DMA */
+static const struct board_blacklist_entry board_blacklist[] = {
+ /* on IEI PCISA-C3 CF adapter pin connectors for DMA are missing */
+ { "FIC" , "PT-2200" , "hdc" },
+ { NULL , NULL , NULL }
+};
static const struct drive_list_entry drive_whitelist[] = {
{ "Micropolis 2112A" , NULL },
@@ -207,6 +222,30 @@ void ide_dma_on(ide_drive_t *drive)
drive->hwif->dma_ops->dma_host_set(drive, 1);
}
+static int __ide_dma_bad_adaptor(ide_drive_t *drive)
+{
+ const struct board_blacklist_entry *table = board_blacklist;
+
+ const char *board_vendor = dmi_get_system_info(DMI_BOARD_VENDOR);
+ const char *board_name = dmi_get_system_info(DMI_BOARD_NAME);
+
+ if (!board_vendor || !board_name)
+ return 0;
+
+ for ( ; table->board_name ; table++)
+ if ((!strcmp(board_vendor, table->board_vendor)) &&
+ (!strcmp(board_name, table->board_name)) &&
+ (!strcmp(drive->name, table->drive_name))) {
+ printk(KERN_WARNING "%s: Disabling (U)DMA for %s "
+ "(Board %s %s is blacklisted)\n", drive->name,
+ (char *)&drive->id[ATA_ID_PROD], board_vendor,
+ board_name);
+ return 1;
+ }
+
+ return 0;
+}
+
This code doesn't anyhow discriminate the case of on-board CF and say
normal IDE PCI card plugged into such board -- with latter having no issues
with DMA whatsoever. E.g. AMD Geode GX2 dev. board (DB2301) has CF slot (with
unsoldered DMA pins, IIRC) and 3 PCI slots where you can plug a normal IDE card.
MBR, Sergei
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