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

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Hello, I wrote:
[PATCH] ide: rework the code for selecting the best DMA transfer mode 


Depends on the "ide: fix UDMA/MWDMA/SWDMA masks" patch.
I'm now trying to rewrite hpt366.c to benefit more from these patches... and alas, this very patch seems to be breaking filtering (at least) in this driver. :-] 

 Ignore me, I've seemingly misundertood the code. :-<


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); 
+            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. :-)
@@ -576,10 +564,10 @@ static u8 hpt3xx_ratefilter(ide_drive_t /* fall thru */ 
         case 0x00:
         default:
-            speed = min_t(u8, speed, XFER_MW_DMA_2);
+            mask = 0x00;
             break;



  Well, that case 0x00 should never actually happen.


  Yeah, that's true, 'case 0x00' (and even 'default') labels could have been removed.

MBR, Sergei

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