Re: [PATCH 14/15] ide: rework the code for selecting the best DMA transfer mode

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello, I wrote:

Index: b/drivers/ide/pci/hpt366.c
===================================================================
--- a/drivers/ide/pci/hpt366.c
+++ b/drivers/ide/pci/hpt366.c
@@ -513,43 +513,31 @@ static int check_in_drive_list(ide_drive
     return 0;
 }
-static u8 hpt3xx_ratemask(ide_drive_t *drive)
-{
-    struct hpt_info *info    = pci_get_drvdata(HWIF(drive)->pci_dev);
-    u8 mode            = info->max_mode;
-
-    if (!eighty_ninty_three(drive) && mode)
-        mode = min(mode, (u8)1);
-    return mode;
-}
-
 /*
  *    Note for the future; the SATA hpt37x we must set
  *    either PIO or UDMA modes 0,4,5
  */
- -static u8 hpt3xx_ratefilter(ide_drive_t *drive, u8 speed)
+
+static u8 hpt3xx_udma_filter(ide_drive_t *drive)
 {
     struct hpt_info *info    = pci_get_drvdata(HWIF(drive)->pci_dev);
     u8 chip_type        = info->chip_type;
-    u8 mode            = hpt3xx_ratemask(drive);
-
-    if (drive->media != ide_disk)
-        return min(speed, (u8)XFER_PIO_4);
+    u8 mode            = info->max_mode;
+    u8 mask;
switch (mode) {
         case 0x04:
-            speed = min_t(u8, speed, XFER_UDMA_6);
+            mask = 0x7f;
             break;
         case 0x03:
-            speed = min_t(u8, speed, XFER_UDMA_5);
+            mask = 0x3f;
             if (chip_type >= HPT374)
                 break;
             if (!check_in_drive_list(drive, bad_ata100_5))
                 goto check_bad_ata33;
             /* fall thru */
         case 0x02:
-            speed = min_t(u8, speed, XFER_UDMA_4);
+            mask = 0x1f;
/*
              * CHECK ME, Does this need to be changed to HPT374 ??
@@ -560,13 +548,13 @@ static u8 hpt3xx_ratefilter(ide_drive_t !check_in_drive_list(drive, bad_ata66_4))
                 goto check_bad_ata33;
- speed = min_t(u8, speed, XFER_UDMA_3);

 Hm, found a buglet in my former filtering rewrite -- the condition in the preceding if stmt should be a reverse one, and speed limitation to XFER_UDMA_3 should have been left under it.  With the current code, XFER_UDMA_2 limitation wouldn't have been applied if the same drive is not in both 'bad_ata66_4' and 'bad_ata66_3' lists -- this, however, actually is not the case since WDC AC310200R drive is in both these lists (maybe I wrote it this way because of this fact :-).

+            mask = 0x0f;
             if (HPT366_ALLOW_ATA66_3 &&
                 !check_in_drive_list(drive, bad_ata66_3))
                 goto check_bad_ata33;
             /* fall thru */
         case 0x01:
-            speed = min_t(u8, speed, XFER_UDMA_2);
+            mask = 0x07;
check_bad_ata33:
             if (chip_type >= HPT370A)

This case 0x01 will *never* be hit for HPT370 chip with the new code, therefore the filter won't get applied.

Oh, and for HPT36x chips used with 40c cable too (unless they're artificaially reduced to UltraDMA/33 by the driver #define's).

It will still get applied since the code always resorts to looking up the 'bad_ata33' list for HPT36x/370. I've got a bit muddled in my own code -- not sure if it got much clearer after I'd untangled hpt3xx_ratemask() / hpt3xx_ratefilter() puzzle. :-)

 Yeah, I'm definitely having trouble understanding my own code after some months have passed... :-/

MBR, Sergei

-
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Filesystems]     [Linux SCSI]     [Linux RAID]     [Git]     [Kernel Newbies]     [Linux Newbie]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Samba]     [Device Mapper]

  Powered by Linux